Methods of forming a fiber reinforced pipe on an inflatable mandrel

ABSTRACT

A method and apparatus is provided for continuously making fiber reinforced plastic pipe in which a conveyor tube is formed on an axially fixed hollow rotatable mandrel. A plurality of bands of resin impregnated fiber elements are wound on the conveyor tube as it advances to provide the pipe assembly. The terminal end of the generated pipe assembly is sealed with a plug. A fluid under pressure is fed through the hollow mandrel and out the forward end of the mandrel into a chamber formed by the generated pipe assembly, the plug, and a fluid sealing means within the pipe assembly being generated, thereby causing the pipe assembly to advance.

This application is a continuation-in-part of application Ser. No.577,035, now Pat. No. 3,507,412, filed Sept. 2, 1966, which in turn is acontinuation-in-part of application Ser. No. 387,372, filed Aug. 4,1964, now abandoned, of which application Ser. No. 705,564, filed Feb.14, 1968 is a continuation.

The invention relates to improvements in methods and apparatus formaking substantially rigid, fiber reinforced plastic pipe.

A primary object of the invention is to provide a system forautomatically and continuously making fiber reinforced plastic pipeunder controlled conditions to thereby furnish pipe of uniform thicknesshaving a uniform amount of reinforcing material and resin at all pointsaround its circumference and throughout its length.

Another object of the invention is to provide an automatic, continuoussystem for fabricating fiber reinforced plastic pipe wherein the meansfor continuously advancing the pipe being generated through the systemconstitutes a fluid or air under pressure.

A further object of the invention is to provide an automatic, continuoussystem for fabricating pipe of the type under consideration wherein asingle source of power acts to rotate the pipe assembly being fabricatedand to operate various devices serving to incorporate material into thepipe assembly as it is generated and is combined with the air pressuremeans acting to longitudinally advance the pipe assembly through thesystem.

Another object of the invention is to provide a method and apparatus forthe automatic and continuous manufacture of pipe which includesproviding a conveyor tube acting as a base for the assembly thereon ofthe various elements which will constitute the finished pipe, whereinthe conveyor tube is constructed to include means permitting theconveyor tube to be readily stripped from the completed pipe assembly.

To realize the foregoing objectives with regard to an automatic andcontinuous system for making pipe, a number of novel devices areprovided which, while they are particularly suitable parts of thesystem, are also suitable for other applications or uses. Accordingly,another object of the invention is to provide novel means forcontrolling and synchronizing the linear advancement of a cylindricalendless tube or pipe in relation to the rate of rotation of thecylindrical body.

Still another object of the invention is to provide a novel means forhelically applying a band of parallel arranged continuous fiber elementsto an advancing hollow tubular member and to coat the fiber elements asthey are being applied.

Still a further object of the invention is to provide a belt system of anovel construction which is adapted to enable the formation thereon of atube made essentially from a resinous composition.

Another object of the invention is to provide an improved device forcoating a continuously advancing strip or sheet.

Still another object of the invention is to provide plug meansinsertable in a fluid or air filled pipe or the like which affordssuitable gripping of the pipe and a seal preventing the loss of pressurewithin the pipe, the plug seal means being constructed so that when itis unclamped from the pipe the fluid under pressure is vented prior tothe device releasing its grip on the pipe.

Still a further object of the invention is to provide an inflatablesealing device arranged to grip the interior of a moving pipe assemblyfor movement therewith, means being provided to return the device toinactive position when deflated for reactivation and movement with thepipe.

BRIEF DESCRIPTION OF THE DRAWINGS

These, and other objects and advantages of the invention will beapparent from the following description, taken in conjunction with thedrawings illustrating several preferred embodiments of the invention, inwhich:

FIGS. 1, 1A and 1B together are a schematic showing of a continuoussystem for making pipe in accordance with one embodiment of theinvention;

FIGS. 2-2E together represent a top plan view of apparatus for makingpipe in accordance with the embodiment of the invention schematicallyillustrated in FIG. 1;

FIGS. 3-3E are a side elevational view of the apparatus shown in FIGS.2-2E;

FIGS. 4-4D taken together are a longitudinal cross-sectional view of themandrel and its associated parts;

FIG. 5 is an elevational view partly in cross-section looking in thedirection of the arrows 5--5 of FIG. 4A;

FIG. 6 is an elevational view partly in cross-section looking in thedirection of the arrows 6--6 of FIG. 4A;

FIG. 7 is a vertical cross-sectional view taken approximately in theplane of line 7--7 of FIG. 4A;

FIG. 8 is a vertical cross-sectional view taken approximately in theplane of line 8--8 of FIG. 4B;

FIG. 9 is a vertical cross-sectional view taken approximately in theplane of line 9--9 of FIG. 4B;

FIG. 10 is a front elevational view of means for coating a strip to bewound upon the mandrel to provide a conveyor tube component of a pipeassembly which in one embodiment of the invention becomes an integralpart of the finished product;

FIG. 11 is a side elevational view looking toward the right side of thedevice shown in FIG. 10;

FIG. 11A is a partial plan view showing the manner in which a resincomposition is applied to a carrier strip by the device shown in FIGS.10 and 11;

FIG. 11B is a side elevational view of the elements shown in FIG. 11A;

FIG. 12 is a side elevational view of means for guiding and impregnatingcontinuous fiber elements for application to the conveyor tube insubstantially circumferential windings;

FIG. 13 is a front elevational view of the device shown in FIG. 12, thisview also showing the manner in which the partially fabricated pipeassembly is supported at this station in the apparatus;

FIG. 14 is a front elevational view of a winding head;

FIG. 15 is a side elevational view, partly in section, looking in thedirection of the arrows 15--15 of FIG. 14;

FIG. 16 is an enlarged, partial side elevational view showing the meanson a winding head for guiding the continuous fiber elements onto thepipe assembly being generated;

FIG. 17 is a section taken approximately in the plane of line 17--17 ofFIG. 14;

FIG. 18 is a longitudinal cross-sectional view of the plug used to sealthe forward end of the moving pipe assembly;

FIG. 19 is a view similar to FIG. 18, this view showing the seal plug inits released condition;

FIG. 20 is a vertical cross-sectional view taken approximately in theplane of line 20--20 of FIG. 18;

FIG. 21 is an end elevational view, partly in cross-section, looking inthe direction of the arrows 21--21 of FIG. 18;

FIG. 22 is a side elevational view of the means for controlling theadvancement of the pipe assembly through the apparatus;

FIG. 23 is a vertical cross-sectional view taken approximately in theplane of line 23--23 of FIG. 22;

FIG. 24 is a vertical cross-sectional view taken approximately in theplane of line 24--24 of FIG. 22;

FIG. 25 is a front elevational view of the device shown in FIG. 22;

FIG. 26 is a vertical cross-sectional view taken approximately in theplane of line 26--26 of FIG. 25;

FIG. 26A is a diagrammatic showing of means for sensing axial thrustwhich may be imposed upon the means for controlling the advancement ofthe pipe assembly;

FIG. 27 is a longitudinal cross-sectional view, partly in elevation,showing inflatable means cooperative with the fabricated pipe assemblyto prevent the loss of fluid or air pressure within the pipe assemblywhen a section of the continuously fabricated pipe assembly is cut off;

FIG. 28 is a view similar to FIG. 27, except that a fluid seal plug isshown positioned in the forward end of the continuously fabricated pipeassembly, whereupon the inflatable fluid sealing means cooperative withthe pipe as shown in FIG. 27 is not exercising its function;

FIG. 29 is a vertical cross-sectional view taken approximately in theplane of line 29--29 of FIG. 27;

FIG. 30 is a vertical cross-sectional view taken approximately in theplane of line 30--30 of FIG. 27;

FIG. 31 is a vertical cross-sectional view taken approximately in theplane of line 31--31 of FIG. 27;

FIG. 32 is an enlarged longitudinal cross-sectional view showing theinflatable means cooperative with the pipe assembly when such means isacting to prevent the loss of pressure within the pipe assembly;

FIG. 33 is a longitudinal cross-sectional view showing the relationshipof spring means used in conjunction with the inflatable seal means whichallows the movement of the inflatable seal means with the advancing pipeassembly;

FIG. 34 is an enlarged longitudinal cross-sectional view showing themanner in which the spring means is anchored to the inflatable sealmeans;

FIG. 35 is a breakaway showing of pipe which may be made with theapparatus shown in FIGS. 1-34;

FIG. 35A is an enlarged section taken in the plane of line 35A--35A ofFIG. 35;

FIG. 36 is a schematic showing of means for forming a conveyor tubewhich is removable from the completed pipe assembly;

FIG. 37 is a top plan view of that portion of the apparatus for making aconveyor tube portion which is removable from the pipe assembly;

FIG. 38 is a side elevational view of the apparatus shown in FIG. 37;

FIGS. 39 and 39A together are a side elevational view, partly brokenaway and in section, showing the relationship of the means for applyingseveral of the components of the removable conveyor tube to the mandrel;

FIG. 40 is an elevational view partly in cross-section looking in thedirection of the arrows 40--40 of FIG. 39;

FIG. 41 is an elevational view partly in cross-section looking in thedirection of the arrows 41--41 of FIG. 39;

FIG. 42 is a breakaway showing of a pipe assembly made in accordancewith the embodiment of the invention schematically illustrated by FIGS.36, 1A and 1B taken together, and structurally shown in FIGS. 37, 38,2A-2E and 3A-3E taken together;

FIG. 42A is a vertical section taken in the plane of line 42A--42A ofFIG. 42;

FIG. 43 is a side elevation taken in partial cross section of anotherembodiment of the invention for providing an air seal within thegenerated pipe and of another embodiment of the invention for forming aconveyor tube on the mandrel;

FIG. 44 is a cross-sectional view taken as indicated by the lines andarrows 44--44 of FIG. 43;

FIG. 45 is a cross-sectional view taken as indicated by the lines andarrows 45--45 of FIG. 43;

FIG. 46 is a cross-sectional illustration with parts broken awayschematically illustrating another embodiment of the invention forforming continuous glass-reinforced plastic pipe; and

FIG. 47 is an enlarged cross-sectional view taken through the formedpipe and mandrel structure of FIG. 46.

SUMMARY OF THE INVENTION

In accordance with the invention generally, substantially rigid, fiberreinforced plastic pipe is made automatically and continuously with aminimum of power requirements considering the mass of the materials(glass, resin, etc.) being processed and conveyed through the line. Thisis accomplished by utilizing a fluid or air under pressure to furnish anaxially or longitudinally directed thrust to linearly advance the pipeassembly being fabricated. Such manner of using air pressure furnishes acomponent of force in a radial or circumferential direction with respectto the pipe assembly being advanced by such application of pressure,which assists in the various operations wherein materials are beingdrawn off and circumferentially wound into the pipe assembly.

DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring to FIGS. 1, 1A and 1B, the method of the invention generallycomprises providing an air impervious tube T on an axially fixed,hollow, rotatable mandrel which is generally designated A. The mandrelis provided on the exterior thereof with means B to furnish an air sealwith the interior of the conveyor tube as the conveyor tube is advancedover the mandrel. A plurality of bands a and b of resin impregnatedcontinuous fiber elements are wound onto the conveyor tube T to providea pipe assembly P (FIGS. 35 and 35A). The pipe assembly is rotated asthe pipe assembly is continuously advanced through the apparatus. Airunder pressure is directed through the mandrel and out from the forwardend 50 thereof into the interior of the pipe assembly as the assembly isbeing generated. The forward end of the pipe assembly is closed off byan end closure or plug seal means C so that the pipe assembly, togetherwith the seal portion B of the mandrel and the plug seal means, providea sealed chamber. The air under pressure within the sealed chamberimparts an axially directed thrust to advance the pipe assembly. Ineffect, the sealed chamber is expanded axially or longitudinally as theair under pressure acts to impart forward movement to the processedpipe. To synchronize and control the various operations involved infabricating the pipe assembly, means D is provided for controlling therate of linear advancement of the pipe assembly.

In greater detail, FIGS. 2-2E and FIGS. 3-3E illustrate the apparatusfor the continuous manufacture of pipe in accordance with one preferredembodiment of the invention. The apparatus is provided with a framestructure comprising transversely spaced, longitudinally extending lowersupport members 52 and a central, longitudinally extending upper supportmember 54 secured together by frame members 56 in any suitable manner asby bolting or welding. The frame structure provides means for supportingone end of the mandrel A.

The mandrel A comprises means for furnishing a number of purposes andfunctions as will subsequently appear, and includes a cylindrical,hollow tube 57 which is fixed against axial movement and mounted forrotation. This tube portion of the mandrel provides the means forconveying air under pressure to linearly advance the pipe assembly as itis fabricated and to support a plurality of means for the processing ofseveral elements incorporated in the pipe assembly. The tube 57 is of astructurally rigid material such as stainless steel. At the beginning ofthe line, means is provided for journaling one end of the tube and toprovide means for directing fluid or air under pressure axially throughits interior and out from the forward or opposite end 50.

Referring to FIG. 4, a stationary coupling member 58 is provided andheld to prevent its rotation in any suitable manner. The rear end of thetube 57 is rotatably supported within the interior or central bore 60 ofthe stationary coupling member for a portion of the member's length.Also positioned within the bore 60 is a rotary coupling 62 having aportion 64 of reduced diameter which is received within the interior ofthe tube 57 with a close fit. The tube and the rotary coupling areconnected to one another for rotation together by a roll pin 66. Theportion 68 of the rotary coupling having a larger diameter is of adiameter slightly less than the diameter of the bore 60 of thestationary member. O-rings 70 and 72 provide fluid or air sealing meansbetween the rotary coupling and the associated stationary couplingmember, and between the tube and the stationary coupling member. Therotary coupling 62 is held within the stationary coupling member 58 by abolt 74 and a washer 76 at one end and at the other end by a collar 78which is secured to tube 57 by a cap screw 80. By the describedarrangement, the tube 57 and the rotary coupling connected thereto aremounted for rotation together. Axial longitudinal movement of the tube57 is prevented by a collar 73 secured to the tube by a setscrew 75, thecollar abutting a pillow block 77 bolted to a plate 79 which is fixed tothe standard 56.

As also shown in FIG. 4, means is provided for directing air underpressure axially through the interior of the tube 57 so that the air maybe confined and pass through the tube and out from the forward end 50 ofthe mandrel, which opens into the pipe assembly as the assembly is beingfabricated. The stationary coupling member 58 is provided with athreaded opening 82 extending through the wall thereof within whichthere is screwed a fitting 84 connected to a suitable source ofcompressed air (not shown). In order that the compressed air may haveaccess to the interior of the hollow tube, the stationary couplingmember is provided with a section 86 of increased inner diameteradjacent the opening 82 and adjacent the outer wall of the mandrel.Also, the wall of the tube is provided with a series ofcircumferentially spaced orifices 88 adjacent the section 86 to placethe interior of the mandrel in communication with the line to the sourceof compressed air.

As also shown in FIG. 4, a second line for conveying air under pressureis provided. The stationary coupling member 58 is provided with a secondopening 90 extending through the wall thereof to receive a secondfitting 92 connected to a source of compressed air (not shown). Therotary coupling 62 is provided with a diametrically extending channel 94to place the central bore 96 of the rotary coupling in communicationwith the second air line. A second tube 98 of substantially smallerdiameter than the inner diameter of the tube 57 extends throughout thelength thereof and beyond to convey the air under pressure from thesecond source to inflatable means E (FIG. 1B and FIGS. 21-28) having thepurpose and function to be subsequently described. One end of the tube98 is force-fitted or otherwise secured within the bore of a hollowconnecting member 100, the opposite end of the connecting member beingsuitably secured within the bore 96 of the rotary coupling 62. As shown,such connection may be accomplished by providing mating tapered portionson the rotary coupling head and on the tube connecting member andforce-fitting the parts. By the described arrangement, the air line ortube 98 is connected for rotation with the rotary coupling and with thetube 57 through which it extends.

In the embodiment of the invention illustrated in FIGS. 1, 1A and 1B,and FIGS. 2-3E, the air impervious conveyor tube T is a resin linerwhich becomes an integrated part of the completed pipe assembly.Accordingly, the mandrel A is provided with means permitting theformation of a tubular resin liner while allowing this form of conveyortube to be rotated and advanced with respect to the mandrel withoutadhering to the mandrel. Such means, designated F, is illustratedschematically in FIG. 1 and structurally in FIGS. 4A, 4B, 4C, 4D andFIGS. 5-9.

Essentially, the means F comprises a system of flexible, endless beltsmade of or comprising a flexible material coated with a mold releasematerial. Examples of suitable mold release materials or materials towhich a wet, sticky resin composition will not adhere are atetrafluoroethylene polymer (Teflon), polypropylene, or the like. Thebelts, which are not powered, are arranged to rotate with the mandreland to travel longitudinally with their longitudinal edges slightlyoverlapping to, in effect, provide a continuous, longitudinally movabletube. Whatever longitudinal movement is imparted to the belts is causedby the linear advancement which is imparted to the pipe assembly P ofwhich the conveyor tube is a part.

As shown in FIGS. 4A, 4B, and 5-8, the mandrel A includes a belt supportsleeve 102 over which a plurality of belts may travel longitudinally tofurnish a movable tube of non-adherent material. The belts which will bereferred to as the outer belts 104 and inner belts 106, have theirlongitudinal edges slightly overlapped as they travel over the sleeve102 as shown in FIG. 7. The diameter of the belt support sleeve 102 isselected to furnish, with the added thickness of the belts, the innerdiameter desired for the completed pipe. The belt support sleeve isconnected to the tube 57 by a spider supporting member 108. The spiderform of support means used here and elsewhere in connection with thebelt system furnishes the desired supporting function while allowing thebelts to extend and run through such form of support. The spider 108 issupported on its inner diameter by a sleeve 107 secured to the tube 57by a set screw 109 (FIG. 4A).

As shown in FIGS. 4A, 4B, and 5, the plurality of outer belts 104, hereshown to be three in number, is supported so that at one end they passaround respective spaced rollers 110. The rollers are supported upon aspider assembly 112 having circumferentially spaced support arms 114upon which the respective rollers 110 are mounted for rotation on pins116. The spider assembly 112 is fastened to a sleeve 118 as by welding,the sleeve closely surrounding the tube 57. The sleeve and associatedmounting for the rollers 110 may be adjusted along the length of thetube to the desired position and secured in place by a set screw 120(FIG. 4A).

As shown in FIGS. 4A, 4B and 5, a similar arrangement is provided forthe mounting of the inner belts 106 at one of their ends. Asillustrated, the inner belts are also three in number. Rollers 122 whichrespectively support the inner belts are located however on a smallerdiameter than the diameter prescribed by the outer belt rollers 110. Theinner belt rollers 122 are mounted upon a spider assembly 124 havingcircumferentially spaced support arms 126 upon which the respectiverollers 122 are mounted for rotation on pins 128. Similarly, the spiderassembly 124 is fastened to a sleeve 130 as by welding. The sleeve whichclosely surrounds the tube 57 is adjustable along the length of the tubeto the desired position, and is secured in place by a set screw 132 tolocate the rollers 122 in desired position lengthwise of the mandrel.

As shown in FIGS. 4A and 6, guide means may be provided for theintermediate reaches of the belts, and this may be accomplished byproviding a guide member 134 which, like the supporting means for theouter and inner rollers, is located rearward of the belt support sleeve102. The guide member 134 is provided with circumferentially spacedslots 136, there being three to accommodate the three outer belts. Pairsof slots 138, 138' allow the inner belts to run therethrough and arethereby guided. The guide member 134 is maintained in fixed relationshipwith respect to the tube 57 by suspending it from an arm 140 extendinglongitudinally from the spider support 124 for the inner belt rollers.The connection between the arm 140 and the radially extending support124 may be made by a screw connection 142.

The opposite ends of the outer and inner belts 104 and 106 run aboutguide means provided by a belt return guide assembly 143 supported upontube 57 and located down the line from the belt support sleeve 102. Asshown in FIG. 4B, the largest diameter of the guide assembly 143 doesnot exceed the diameter of the belt support sleeve 102 so that theconveyor tube form of resin liner which will be formed on the belts mayrotate and advance through the equipment without interference.

As shown in FIGS. 4B and 8, the belt return guide assembly 143 includesan annular outer belt return guide member 144 provided with spaced slots146 to allow passage around the smoothly rounded portions 148 and thereturn of the outer belts 104. The guide assembly is also provided withan annular belt return guide member 150 having spaced slots 152 for thesupport and return of the inner belts 106. The guide member 150 also isprovided with slots 153 for guiding the outer belts which have a longerreach than the inner belts. The annular return guide members 144 and 150surround the tube 57 but are not fastened thereto. The return guideassembly 143, of which the guide members 144 and 150 are parts, isrotatable with respect to the tube 57 to prevent torque build-up in thebelt system. Accordingly, the guide members 144 and 150 are connected toeach other and to a bearing sleeve 154 which closely surrounds the tube57 but is rotatable with respect thereto. A plurality of longitudinallyextending, circumferentially spaced fork members 156 are connected toand extend rearwardly from a bearing sleeve 154 to connect the guidemembers 144 and 150 to one another and to the bearing sleeve. The partsare connected to one another in any suitable manner as by welding. Thefork members possess the additional function of providing guide meansfor the outer belts, and if desired, a fork member 158 may be pairedwith each fork member 156 for the guiding function. The second forkmember of a pair need not extend to the guide member 150 for connectionthereto, sufficient structural strength being provided by the severalfork members 156 which bridge the guide members and the bearing sleeve.

As also shown in FIG. 4B, the bearing sleeve 154, though rotatable withrespect to the tube portion 57 of the mandrel, is mounted on the tube ina manner to limit its movement in a longitudinal direction. For thispurpose, a collar 160 is positioned on the tube 57 and set in thedesired position by means of a set screw 62. A washer 164 is positionedintermediate the bearing sleeve and the collar. Thus, the collar and theguide assembly 143 cannot move rearwardly on the tube and impartundesirable slack to the belt system after the collar has been properlypositioned on the tube.

As will be evident from FIGS. 4A and 4B, the outer and inner belts 104and 106, after passing over the support sleeve 102, return through itsinterior. To further assist in guiding the belts, a guide ring 166 ispositioned intermediate the support sleeve and the tube 57. Both theouter and inner belts run over the outer periphery of the guide ringwhich is held between collars 168, 168'. The collars are provided withrespective set screws 170, 170' so that the guide ring may be located indesired position along the length of tube 57.

In order that the resin liner form of conveyor tube T formed on thesleeve supported flexible belts may be suitably supported and engaged bythe aforementioned seal means B, the mandrel A includes a second sleeve172 down the line from the belt support sleeve 102. As shown in FIGS. 4Band 4C, the sleeve 172 having a diameter to allow slight clearance withrespect to the conveyor tube which will advance over it surrounds thetube 57. Although the tube 57 may be continued through the sleeve 172,for convenience of assembly the sleeve 172 is provided with an innersupport ring 174 which may be connected to the sleeve 172 as bycountersunk screws 176. The inner diameter of the support ring isconnected to a coupling sleeve 178 fixed to the tube 57 by a set screw179. A tube 57' constituting a continuation of tube 57 is screw threadedto the coupling sleeve 178. The support ring 174 is formed with spacedapertures 181 to allow any air which may escape rearwardly of the sealat B to be vented (FIGS. 4B and 9). As will be subsequently described,the inner seal means B provided by the mandrel is supported by andconnected to the tube 57' and the sleeve 172.

To supply the resin c (FIGS. 35 and 35A) which will furnish the airimpervious conveyor tube T and constitute an integrated part of thefinished pipe assembly, means G is provided as shown in FIGS. 2 and 3,and in greater detail in FIGS. 10, 11, 11A and 11B. It is preferred touse thermosetting resin compositions; for example, an epoxy resincomposition with a suitable hardener or curing agent, polyester resins,or the like. While the resin composition may be applied directly inliquid form to the described belt system, it is preferred that the resincomposition be applied on a carrier strip d which is helically woundonto the belts. Two coating devices G are shown. It is within the scopeof the invention to use but one device. Two devices are used where it isdesired to obtain a resin liner of substantial thickness. The devices Gare identical and the description which follows of one such device isequally applicable to the other.

The resin c is applied to a highly absorbent and porous strip ofmaterial d. The strip material is preferably 12 pound tissue paperhaving a width of approximately 1 inch. As shown in FIGS. 10 and 11, theabsorbent tape or strip d is withdrawn from a roll 180, led around aguide pin 182 and around a guide roll 184 provided with suitable meansfor adjusting tension as is known in the art. The strip then runshorizontally over a guide pin 186 immediately rearward of an endlessdoctor blade 188 which is mounted for continuous movement transverselyof or over and across the path of the horizontally moving strip d. Thedoctor blade, which is in the form of a thin continuous band of steel,is mounted to pass around a pair of longitudinally spaced grooved wheels190, 190'. To power the movement of the doctor blade band, one of thewheels, the wheel 190, has fixed to the rear thereof a gear 192 which isrotated by a gear 193 secured to the shaft of a fractional horsepowermotor 194 connected to a suitable source of current (not shown). Thegear ratios are selected to rotate the wheel 190 and thereby the doctorblade band 188 around such wheel and the opposite idler wheel at adesired regulated and constant speed.

As also shown in FIGS. 10 and 11, the doctor blade band wheels 190, 190'and the doctor blade band 188 are supported in a manner to enable theadjustment of the angle of the band with respect to the strip to becoated. Also, means is provided for the adjustment of tension upon thedoctor blade band.

The band support wheels 190, 190' are mounted for rotation on bearingswithin the respective wheels on shafts extending into support plate 196.The support plate is secured within a U-shaped frame 197 of a thicknesssufficient to allow pivot pins to be extended into its sides. The plateand frame assembly is pivotally connected at each side by threaded pivotpins 198, 198' to longitudinally spaced brackets 200, 200' which arefixed, as by welding, to a cross frame member 202 secured to extendbetween and to one side of a pair of longitudinally spaced framestandards 204, 204'. As shown in FIG. 10, the support plate 196 and itsassociated frame 197 is generally U-shaped to allow passage of thecontinuous strip or tape d over the base portion and between the armportions of the assembly. The support plate and its frame are tiltableabout the pivot pins 198, 198' to enable adjustment of the angle of theband 188 with respect to the plane of the strip d as it is drawn off theroll 180 under controlled tension and guided by the aforementioned guidepins. Then, the support member is releasably secured in position as bywing nuts associated with the pivot pins. In this manner, the amount ofresin applied to the strip may be adjusted at the nip between thetravelling doctor blade and the moving strip (FIG. 11B) forpredetermined rates of movement of the doctor band and of the strip.Means including a screw 206 is provided for adjusting the tension uponthe doctor blade band, such adjustment screw being associated with thebearing for one of the doctor band wheels which is mounted in a mannerto permit the axis of rotation of doctor band wheel 190' to be movedtoward or away from the axis of rotation of the other doctor band wheel.

The liquid resinous material of a suitable viscosity is applied to themoving strip d in any desired manner. It is preferred, however, and asshown in FIGS. 10-11B, to meter the resin composition onto the stripfrom an applicator mixer 208 which, when an epoxy resin composition isused, mixes and meters a controlled amount of resin and hardener indesired proportions onto the strip. The mixer applicator or dispenser isoperated by a fractional horsepower motor connected to a suitable sourceof current (not shown). The liquid resinous composition is applied tothe strip in the form of a stripe 210, as shown in FIG. 11A. As shown inFIG. 11, the mixer applicator is supported upon a bracket 212terminating in a hub 214 mounted for vertical adjustment upon the guiderod 216 to thereby permit adjustment of the mixer applicator withrespect to the strip d. When the strip moves under the band form ofdoctor blade 188, the resin composition is spread across the width ofthe strip for a predetermined thickness determined by the angle of thedoctor blade band, the rates of movement of the doctor blade band andthe strip, and the selected rate of deposition upon the strip of theliquid resin composition by the mixer applicator. To assure that thedoctor blade band is maintained in a clean condition after having servedto spread the liquid resin composition across the width of the movingstrip, a heater 218 positioned to surround the doctor blade band ismounted upon a bracket 220 fastened to the support member 196, as shownin FIG. 10. Preferably, an electric coil type of heater is usedconnected to a suitable source of current (not shown), the heater actingto burn off any resinous material which may adhere to the smooth surfaceof the doctor blade band.

In order that the device G shall not require that its operation bestopped when a roll of strip material is exhausted, a second or readyroll 222 is provided to replace the exhausted roll 180. As also shown inFIGS. 10 and 11, one roll, the roll 180, is mounted upon a spindle 224connected to the top end of a rocker arm 226 pivotally connected at itslower end to a shaft 228 extending between the spaced standards 204,204'. The spindle is provided with the usual spaced plates to confine aroll of the strip material or tape between them. An arcuate member 230is secured at one end to the rocker arm 226, the arcuate member beingprovided with a series of spaced apertures 232. A pin 234 is extendedthrough the adjacent standard and through a selected aperture 232 in thearcuate member 230 to thereby furnish adjustability to the desiredangular position for a roll of strip material. A similar arrangement isprovided for the second roll 222 which is mounted for adjustment todesired position on like numbered parts with respect to the oppositestandard. As will be evident from FIG. 10, when a roll of strip materialor tape is about to be exhausted, the depleted roll may be pivotedaround behind the ready roll which is moved into feeding position aftersplicing. Then, a new roll of strip material is placed in the readyposition.

Where, as preferred, an epoxy resin composition is used to furnish theresin for a liner form of conveyor tube T, the same means for rotatingthe pipe assembly of which the conveyor tube T is a part may be used tosynchronously pump desired amounts of resin and of hardener in regulatedproportions to the mixer 208. For this purpose, means H is associatedwith a coating device G. Where two coating devices are used, there isone resin and hardener supply means for each coating device.

As shown in FIGS. 2, 2A, 3 and 3A, a tank 238 is compartmentized tocontain an epoxy resin composition in one compartment 240 and a hardenercomposition in the other compartment 242. As shown, the tank issupported on legs 244 so that the tank may be located adjacent one ofthe longitudinally extending base frame members 52. A pump 246 isprovided to convey resin from the compartment 240 to the mixerapplicator 208 through a hose 248 and a second pump 250 delivers thehardener composition to the mixer through a hose 252. A hose 254 extendsbetween the resin pump 246 and the resin compartment and another hose256 extends between the hardener compartment and its associated pump250.

Preferably, the pumps 246 and 250 are operated by the same motor whichoperates the winding heads designated I (FIGS. 2B, 2C, 3B and 3C), whichare located forward in the line to helically wind bands of fiberelements b into the pipe assembly P. The single motor for operating thepumps, the winding head I, also the aforementioned means D forcontrolling the rate of linear movement of the pipe assembly, is shownin FIGS. 2D and 3D and is designated 258. For example, when making twoinch diameter pipe, and in conjunction with air pressure as hereinapplied, the motor may be only approximately 1/2 H.P. Air pressure inthe main air line provided by the tube 57 and its extensions isapproximately 40 p.s.i. For 3, 4 and 6 inch diameter pipe, thehorsepower of the motor and the air pressure are of course increased.

As shown in FIGS. 2D and 3D, the shaft of the motor 258 is provided witha pulley 260 about which passes a belt 262 cooperable with a pulley 264fixed to a driving shaft 266. The motor is supported upon a bracket 268secured to a frame member 56'. The driving shaft extends forwardly ofthe machine for cooperation with the linear advance control means D(FIGS. 2E and 3E). The driving shaft, which is journaled to extendthrough longitudinally spaced pillow blocks 267 secured to thelongitudinally extending upper frame member 54 also extends rearwardlyto the winding heads I, and through intermediate coupling means thedriving shaft acts to drive a shaft 268 which operates theaforementioned pumps 246 and 250.

As shown in FIGS. 2B and 3B, the driving shaft 266 extends along the topof the machine and the driven shaft 268 extends along the base of themachine where the latter shaft is journaled to extend throughlongitudinally spaced pillow blocks 270 secured to the base frame member52. This transfer of power from the driving shaft to the driven shaft isaccomplished by a series of pulleys and belts. The end of the drivingshaft 266 is provided with a pulley cooperable with a pulley on one endof a stub shaft 272, the two pulleys receiving a belt 274. The oppositeend of the stub staff is also provided with a pulley over which runs abelt 276, the belt running over a second pulley 278 on an end of a stubshaft 280 located below the stub shaft 272. The stub shaft 280 islocated near the base of the machine whereas the stub shaft 272 issuitably mounted near the top of the machine. The opposite end of thestub shaft 280 is also provided with a pulley 282 cooperable with apulley 284 on the end of the driven shaft 268, these latter two pulleysreceiving a belt 286.

As shown in FIGS. 2, 2A, 3 and 3A, the driven shaft 268 is provided witha pulley 288 adjacent each device H. A belt 290 extends around thepulley and around a second pulley 292 keyed to the shaft of a speedcontrol device 294. A shaft on the opposite side of the control devicehas a pulley 296 keyed thereto to operate a gear reducer 298, such gearreducer providing a shaft having a pulley 300 fixed thereto. A belt 302extends around the pulleys 296 and 300 to actuate the gear reducer. Theshaft extending through the opposite side of the gear reducer isprovided with a centrally positioned gear 304 cooperating with a gear306 for the resin pump 246, and on its opposite side with a gear 308 forthe hardener composition pump 250. Thus, the motor 258 through thedescribed drive arrangement serves to deliver resin and hardener to themixer applicator 208 off the same driving means which actuates a numberof other operations in synchronism throughout the line.

The resin c carried by the absorbent strip or strips d in helicallywound onto the tubular arranged belts 104, 106 supported on the sleeve102. The power to withdraw the strip from its roll and past the doctorblade 188 is furnished by the rotation imparted to the pipe assembly Pand conveyor tube portion T thereof by the driven winding heads I up theline. Between the coating device O and the belt system provided by themandrel, heating means 310 is provided adjacent the path of the resincomposition coated strip d to cause the resin composition to passthrough the porous strip material to the underside thereof, whereby theresin composition is situated on both sides of the strip. The heater 310is shown in FIG. 2 and the resultant relationship of the resin c on eachof the strips d is shown in FIG. 35A.

After the strip d carrying the resin c is helically wound onto thetubular arranged, adhesion resistant belts 104, 106 to form a conveyortube essentially of resin, heat is applied to partially cure to asubstantial extent the resin composition. As shown in FIGS. 2 and 3, aheater or series of heaters 312 are suspended from the central upperframe member 54 by suitable straps 314. The resin liner form of conveyortube T, after having advanced beyond the reach of the belts, passesthrough a cooling device 316 and now constitutes an air impervious tubehaving a substantial measure of rigidity. The tubular resin liner isrotated and advanced in the machine over the aforementioned sleeve 172where the inner surface of the resin conveyor tube is engaged by theseal means B as shown in FIG. 4C.

The fluid seal means B prevents air under pressure which is conveyed outof the end of the mandrel at 50 (FIGS. 1, 1A and 4D) from passingrearwardly of the seal means. Such seal means provides one end of aclosed chamber within the pipe assembly P as the pipe assembly isgenerated by the apparatus, the opposite end of the closed chamber beingsupplied by the aforementioned plug means C which is inserted in theforward end of the advancing pipe assembly.

As shown in FIG. 4C, the seal means B is in the form of a tapered,open-ended cup-like member 318 having an annular bead 320 at its forwardend, the bead being of a diameter to closely engage the inner surface ofthe conveyor tube T which advances thereover and rotates with respecttherewith. A material suitable for furnishing the desiredcharacteristics of providing a seal when engaged with the interior of aconveyor tube while allowing sliding and rotating motion of the conveyortube with respect to the bead portion is rubber or a rubber-likematerial such as silicone rubber. As illustrated, the seal member 318 isheld in position by the clamping action thereupon of a tapered outerclamping sleeve 322 and an inner clamping sleeve 324. The clampingsleeve 322 is preferably made of a tetrafluoroethylene polymer (Teflon).The inner clamping sleeve is internally threaded at 326 and matinglythreaded around the outer diameter of a portion 328 of reduced diameterprovided by a coupling member 330. The coupling member has a portion 332which is received between the sleeve 172 and the air conveying tube 57'.The member 330 is made flush at its exterior with the outer surface ofthe sleeve 172 so that the sleeve 172, the coupling member 330 and theouter clamping sleeve 322 provide a smooth, continuous surface. Theportion 332 of the coupling member 330 is formed to provide a shoulder334 against which is seated an internal flange 336 of the outer clampingsleeve 322. The seal member 318 also has an internal flange 338 which isclamped between the flange 336 and the end of the internal clampingsleeve 324 when the latter clamping member is threaded onto the innertubular portion 328 of the coupling member. The tubular portion 328constitutes an extension of the air conveyor tube 57, 57'. The taper onthe upper clamping sleeve 322 and the uniform thickness of the sealmember 318 rearward of the bead 320 furnishes a firm but resilientmounting for the seal member's bead portion 320.

As shown in FIG. 4D, a set screw 340 is extended through the interiorclamping sleeve 324 and into the tubular portion 328 of the couplingmember to thereby prevent the clamping of the seal 318 from beingloosened from its clamped position. As also shown in FIG. 4D, alongitudinally extending sleeve 342 is secured to the outer surface ofthe tubular portion 324 as by welding. The diameter of the sleeve 342 isless than the inner diameter of the conveyor tube whereby air underpressure passing through the tube 57 and its extensions 57', 328 and 342may pass out of the end 50 and provide an air support intermediate thepipe assembly being generated and the portion of the mandrel forward ofthe annular bead 320 of the seal means.

As schematically shown in FIG. 1A after the conveyor tube has beenprovided on the mandrel, and preferably before the conveyor tube haspassed beyond and over the seal means B, the tube is overwound with alayer a (FIG. 35) of parallel arranged continuous fiber elements guidedand impregnated with a resin composition by a device generallydesignated J. While the continuous elements may be of any suitablefiber, it is preferred to use rovings of glass. At the station where thefirst device J is located, the band of parallel arranged fiber elementsis preferably applied with the fiber elements at an angle ofapproximately 82° to the longitudinal axis of the pipe and, as indicatedin FIG. 35, there are four such layers of windings a, a1, a2 and a3 inthe finished pipe alternated with three layers b1, b2 and b3 of fiberelements laid down at a relatively low angle of approximately 16° and ofopposite hand. It will be understood, however, that the number oflayers, the angles at which the fiber elements are laid into the pipeassembly, the amounts of fibrous material in the respective layers, andthe amount of resin impregnant are a matter of choice depending upon thecircumferential-axial strength ratio desired to provide a balanced pipestructure. The number of winding heads and devices for impregnating thefiber elements and applying layers of fiber elements wound at arelatively high angle used in the line depends upon the number of layersand the amounts of fiber and resin desired in the finished pipe.

Referring to FIGS. 12 and 13, the fiber element guiding and impregnatingdevice 11 comprises a suitably supported tank or bath 344 containing asuitable liquid resin composition. A wheel supporting frame comprising apair of transversely spaced, vertically extending frame members 346,346' is spaced rearwardly of a guide frame member 343. An angledstructural member 348 extends between the two spaced frame supportingmeans. The wheel frame structure also includes the converging structuralmembers 350, 350' extending from the upper ends of transversely spacedframe members 346, 346' to provide an arch arrangement, as shown in FIG.13.

In applying the first layer a of substantially circumferentially appliedwindings to the conveyor tube T, it is not necessary to preliminarilycoat the conveyor tube. Accordingly, the first guiding and impregnatingdevice J in the line may be located to the side of the line, as shown inFIGS. 2B and 3B, and the wheel supporting frame and the relationship ofthe wheels about to be described may be omitted at this station.However, a device J1 will be described to include the arrangement ofwheels because the wheel arrangement has an important function when thedevices J1, J2, and J3 are located immediately forward of and related tothe winding heads I1, I2 and I3, respectively. As shown in FIGS. 2B and2C, the paired devices I1-J1, I2-J2 and I3-J3 are located centrally inthe line beneath and surrounding the advancing conveyor tube T havingthe layer a thereon.

Where for the application of the first layer a of windings to theconveyor tube T, a J1 form of device is located centrally andimmediately adjacent the conveyor tube being generated, the conveyortube is supported and preliminarily coated with a resinous compositionfrom the same bath which impregnates the fiber elements wound as thelayer a onto the conveyor tube. As shown in FIGS. 12 and 13, a coatingwheel 352 is suspended from the frame member 350' by an adjustablymounted bracket 354 providing an axis of rotation 356 for the wheel. Thebracket is slotted to allow its adjustment with respect to the framestructure by screws 358 extending through slots in the bracket and intothreaded openings in the frame member 350'. The coating wheel 352 has aportion thereof submerged within the bath 344. A support wheel 360 isjournaled for rotation on a bracket 362 connected to the frame member350 in a manner to also allow adjustment of the position of this wheel.As shown, the wheels are arranged so that the conveyor tube T issupported by the two wheels. Rotation imparted to the pipe assembly andits conveyor tube portion causes the wheels, which are not otherwisepowered, to rotate whereupon the coating wheel 352 applies a resincoating to the conveyor tube. To confine the conveyor tube upon thecoating and supporting wheels, a guiding wheel 364 is suspended from theframe structure to engage the rotating and advancing conveyor tube at athird point or above the areas where the tube is engaged by the wheels352 and 360. Similarly, the wheels 364 is suspended from a bracket 366adjustably connected to the frame structure.

As also shown in FIGS. 12 and 13, immediately adjacent the describedwheel arrangement and forward thereof, means is provided for guiding andimpregnating the fiber elements which are wound substantiallycircumferentially onto the conveyor tube. The continuous fiber elementswhich furnish the layers a, a1, a2 and a3 are drawn off of packageswhich are stored in containers or the like (not shown) immediately tothe side of the continuous line of equipment. The fiber elements aredrawn from their sources and arranged in side by side, parallelrelationship by passing over a horizontally extending guide bar 368 andbetween upstanding longitudinally spaced guide pins 370 extending fromthe guide bar. The guide bar and its upstanding pins are mounted upon ahorizontally extending frame member 372 fixed to extend between thevertical frame members 343 and 346'. As shown in FIG. 13, the guide barand its pins are positioned rearwardly of the tank which is alsosuspended from the frame member 372 by a suitable bracket 373 secured tothe tank and to the frame member. The continuous fiber elements then areconducted around a series of tensioning guide rods 374, 376, 378 and 380arranged in vertically spaced relationship. The guide rod 374 ispositioned within the tank so that the parallel arranged fiber elementspassing around it are impregnated with the resin composition. The fourhorizontally extending vertically spaced guide rods have a commonsupport plate 382 secured to the cross frame member 372. As shown inFIG. 12, the top support rod is curved and is removably connected to thesupport plate by a nut 384 to allow the presentation of either a concaveor a convex surface to the impregnated band of parallel arranged fibersprior to their being wound onto the conveyor tube. Band width control isobtained by changing the orientation of the curve as provided by theadjustable guide rod in relation to the incident band. A convex surfaceprovides a wider band and a concave surface provides a narrower band.

The coated conveyor tube now covered with a band of substantiallycircumferentially wound resin impregnated fiber elements then advancesto the station where a layer of parallel arranged continuous fiberelements are helically wound into the assembly at a lower angle ofopposite hand by the first winding head I1. The winding head is a devicewhich supports a plurality of spools of continuous fiber elements andwhich rotates around the partially fabricated pipe assembly at acontrolled speed acting to rotate the pipe assembly which, as itrotates, is advanced in an axial or longitudinal direction. The relativemotion of the pipe assembly with respect to the winding head or headsestablishes the angle that the fiber elements are wound into the pipeassembly. The relative motion between the pipe assembly and the rotatingwinding head causes the fiber elements to pay off the spools and coverthe conveyor tube and the initial layer a of fiber element windings.

As shown in FIGS. 14-17, a winding head 11 (the three winding head I1,I2 and I3 are identical) comprises an annular U-shaped channel 386having rings 387 secured as by welding to the outer ends of thechannel's arms (FIG. 17). A pair of laterally spaced annular plates 388,388' are welded to the base portion of the channel member. A series ofequidistantly spaced, circumferentially arranged spindles 390 aresecured to extend from the annular plate member 388 and similarly, aseries of spindles 390' are secured to extend from the annular plate388'. The spindles which are each provided at their outer ends with awasher and screw means are adapted to receive spools of glass rovings orthe like. The comparatively large central opening on the inner diameterof the annular plates 388, 388' is provided with four equidistantlyspaced, radially extending guide support plates 394 which are welded toan internal ring 396 bridging the inner ends of the annular plates 388,388' to thereby provide guide support means as a part of the windinghead. The four equidistantly spaced guide support plates 394 have theconfiguration shown in FIG. 15 and are secured as by welding to theinternal ring 396. The winding head has a central opening 397. As shown,a portion of each plate 394 extends rearwardly of the channel member 386and its associated plates 388, 388'. The major length of the guidesupport plates, however, extends forward of the channel member 386 andits associated plates.

As best shown in FIG. 16, the continuous fiber elements or strands,after being drawn off of the spools, first pass around a ring guide 398and a guide 399 for the strands pair off from the spools on the rearside of the winding head. Then, each of the fiber elements or rovingspasses through a ring provided with circumferentially spaced eyelets400, one eyelet for each roving. The rovings then run over the ringguide 402, around the adjustable tension guide ring 404, over the guidering 406 and around through the central opening 403 in a guide plate408. The adjustable guide ring 404 is secured as by welding to brackets405, there being one bracket for each plate 394. The brackets are eachsecured by a bolt in one of a series of holes 407 in the respectiveplates 394. The guide plate 408 is secured to the lower ends of thecircumferentially spaced brackets 405. Except for the adjustably mountedguide ring 404, the guide rings 398, 399, 402 and 406 and the ringproviding the support for the eyelets 400 are fixed to the plates 394.The center of the winding head at the opening 403 allows the conveyortube with the wound layer or layers thereon to pass centrally throughthe head for the application of a layer b1, or layers b2 and b3, uponsuch generated portion of the pipe assembly.

As shown in FIGS. 14 and 15, each winding head is supported for rotationby a framework 410 which comprises a pair of transversely spaced,vertical standards 412, 412' connected by pairs of vertically spacedcross members 414, 414' at the top and bottom. Angled bracing andload-bearing members 416, 416' extend between the frame members 412 and414' on opposite sides of the frame structure. The angled members havemounted thereon loadbearing rollers 418, 418', each comprising spacedpairs for engagement with the spaced rings 387 forming the rims of thewinding head. The bracing members also are used to support bearingmembers 420, 420' which are received intermediate the arms of theU-shaped channel to maintain the winding head on center as it rotates. Athird positioning bearing 420" is located centrally from the top crossmember 414. The winding head with a full complement of spools mountedthereon and the described guide means for the plurality of fiberelements is rotated by the drive shaft 266 which rotates a pulley 422fixed to the shaft. A belt 424 extends around the pulley and is receivedand bears against the base portion of the U-shaped channel 386 to rotatethe winding head at a selected rate of rotation depending upon the sizeof the pulley 422 for a given rate of rotation of the drive shaft 266.Preferably, a tension wheel 425 mounted on the cross member 414 isprovided to take up any slack in the belt 424.

With the winding heads I1, I2 and I3 positively rotated about the pipeassembly as it is generated, and with the substantial forces to beovercome in drawing off the fiber elements under tension from a numberof spools sufficient to provide the bands b1, b2 and b3 each of a widthsubstantially equal to the circumference of the generated portion ofpipe assembly, the winding heads act to rotate the rotatably mountedpipe assembly. The parallel arranged fiber elements drawn off eachpowered winding head pass through the central opening 403 in the form ofa frusto-conical structure before the fiber elements are laid into thepipe assembly and with a device J located immediately adjacent eachwinding head as shown, the fiber elements are engaged by theaforementioned wheels 352, 360 and 364. As a result, a resin coating isapplied to the fiber elements by the coating or impregnation wheel 352as the moving tapered arrangement of fiber elements revolves in contactwith the wheel. The same bath used to coat the fiber elements for alayer a coats the elements for a layer b. The support wheel 360 acts asa support for the generating pipe, and by its rotation also causes thefiber elements of the frusto-conically arranged, parallel fiber elementsto be flexed, thereby assisting to force resin composition into thetravelling fiber elements. The associated guide wheel 364 also functionsto impart flexure to the moving fiber elements as they pass under thewheels and are wound onto the conveyor tube with its previously appliedlayers of fiber elements. At the pair of associated devices J1-I1, aband b1 of resin impregnated continuous fiber elements wound at arelatively low angle is immediately overwound by a band a1 of resinimpregnated continuous fiber elements applied at a substantially highangle and of opposite hand. Similarly, the bands or layers b2-a2 andb3-a3 are applied from the associated devices I2-J2 and I3-J3,respectively. The resin coating or impregnant is preferably athermosetting resin composition such as an epoxy resin composition and asuitable hardener or a polyester composition.

When the generated pipe assembly passes the station of the last group ofrelated devices I3-J3, the pipe assembly moves under a heater 426 tocure the resin impregnant for the fiber elements in the various layerswhich have been incorporated into the pipe assembly. As shown in FIGS.2C-3E, the heater is suspended from straps 428 connected to the centralupper frame member 54 so that the heater is located immediately adjacentthe advancing pipe assembly. The pipe assembly then passes into an oven430 which may have a communicating blower 432. The pipe assembly thenpasses through a cooling device 433, whereupon the pipe assembly is in acondition suitable for field use. The pipe assembly however is utilizedto furnish an operating part of the apparatus which continuouslymanufactures the pipe assembly.

As will be evident from FIGS. 1-1B and FIGS. 2-3E, the control means Dand the inflatable seal means E are the next devices forward in the lineprovided by the apparatus. It is believed, however, that the inventionmay be best explained by now describing the functions of the air underpressure which is conveyed through the mandrel by means of the tube 57and its extensions 57', 328 and 342. The aforementioned seal means B maybe located anywhere beyond the station where the conveyor tube is formedon the mandrel. Such seal means may be provided at a point just prior tothe location of the first device J where the layer a is applied. Theconveyor tube is sufficiently rigid to withstand the tension of thewindings applied from the device J. As shown in FIG. 1A, it is preferredto locate the seal means B forward of the first winding head I1. Whilethe end 50 of the mandrel may be located at any point forward of theseal means B, it is preferred that the end of the mandrel be locatedimmediately following that point on the mandrel where the winding head13 is located or rearward of the control means D. The air under pressurewithin the pipe assembly, and down from the mandrel, acts to resist thepressure of means gripping the pipe assembly provided by the controlmeans D.

As previously indicated, the primary function of the air under pressureis to impart an axial thrust to the pipe assembly as it is beingfabricated to continuously advance the assembly through the apparatus.It will of course be understood that when the apparatus is started, adummy length of pipe may be used to initiate operation of the equipment.When the forward extremity of the generated pipe assembly is beyond thecontrol means D and the inflatable seal means E, plug seal means C isused to seal the forward end of the pipe assembly so that a rigid bodyis provided against which the force of the fluid or air under pressuremay exert its thrust. While any suitable plug means may be used, it willbe apparent that a very strong, air-tight connection must be madebetween the end of the pipe assembly and the plug. A plug constructionwhich is particularly serviceable for the purpose and which is preferredis shown in FIGS. 18-21.

As illustrated, the plug seal means C comprises an annular bearing plate434 having a central, internally threaded opening 436. A hand wheel 438is provided with a longitudinally extending externally threaded shaft440 which extends through the mating internally threaded opening 436.The hand wheel and the shaft are fixed for rotation together by a torquepin 442. The forward end of the shaft has a disk 444 fixed to it of alarger diameter than the diameter of the shaft for engagement with ashoulder 446 provided by an inner plug 488. An O-ring 450 is positionedadjacent the rear side of the disk for sliding sealing engagement withthe wall of a central bore 452 extending rearwardly of the shoulder 446.The O-ring is confined between the disk and an annular flange 453 formedon the shaft 440. The plug 448 is hollow and has a counterbore 454 oflarger internal diameter in communication with the smaller bore 452,whereby the disk 444 has clearance when the hand wheel is turned tocause axial movement of the shaft 440 and the unseating of the disk fromthe shoulder 446. A stop collar 456 is fastened to the shaft 440 tolimit the extent of rotation of the shaft to its unclamped position(FIG. 19), the collar engaging an internal shoulder 458 provided by theplug 448.

As shown in FIGS. 18 and 19, the plug 448 is formed to provide afrusto-conical outer surface whereby a ramp 460 is provided convergingin taper from the end 462 of the plug rearwardly toward the bearingplate 434. A split, expandible sleeve comprising a plurality of segments464 overlies the plug 448. As shown in FIG. 20, four split sleevesegments may be used, and as illustrated, each segment is connected tothe bearing plate 434 by a bolt 466 extended through an aperture 468 inthe bearing plate. The bolt for each segment is matingly threaded into athreaded bore 470 provided to extend longitudinally in each segment, andlocked by a set screw 471 so that the head of each bolt is spaced fromthe bearing plate. The apertures 468 in the bearing plate however are ofa diameter to furnish clearance with the shanks of the bolts 466 wherebythe segments furnishing the annular split sleeve may possess movement ina radial direction. An elastic retaining ring 472 of rubber or the likeencompasses the sleeve segments to resiliently maintain the segmentsagainst the underlying plug 448. Each segment is formed so that itsinner surface has a taper for mating engagement with the plug's ramp460. The external surface 474 of each segment is roughened as byknurling or the like to furnish a gripping surface for engagement withthe internal surface of the pipe. An elastic O-ring 476 located tosurround the plug 448 at the forward edge of the split, expandiblesleeve assembly prevents air leakage between the inner plug and the pipeassembly when the plug seal means C is in operative position and clampedwithin the forward and of the pipe assembly P (FIG. 18).Circumferentially spaced, air venting openings 478 are provided inbearing plate 434 to place the interior of the plug 448 in communicationwith the ambient atmosphere when the O-ring 450 is moved out of the bore452 (FIG. 19). To assure continued venting though the stop collar may bein engagement with the shoulder 458, vent holes 480 may be extendedthrough the collar.

The operation of the plug seal means C will be apparent by a comparisonof FIG. 18 showing the device in its pipe clamping position and FIG. 19showing the device in its unclamped position. With the device in itsunclamped position, the split, expandible sleeve is on its smallestdiameter since the segments 464 are positioned on the smaller diameterof the tapered ramp 460. When the hand wheel 438 is rotated to clamp,the plug is drawn inwardly within the split, expandible sleeve so thatthe segments 464 ride up on the ramp 460 until the knurled surfaces 474grip the inner surface of the pipe assembly with a firm, air-tight seal.Such relative motion of the parts causes the elastic, retaining ring 472to increase in diameter. In clamped position, the disk 444 engages theshoulder 446 and the O-ring 450 is in sealing engagement with the wallof the bore 452. When the hand wheel 438 is turned in an oppositedirection to unclamp the device from the pipe, the O-ring seal 450 isunseated from the wall of the bore 452, and causes the venting of theair pressure within the pipe assembly through the communicating openings478. The parts are dimensioned so that such venting takes place whilethe knurled segments still maintain their grip on the pipe assembly,thereby preventing the device from being blown out of the pipe. Furtherrotation of the hand wheel allows the bearing plate 434 and itsconnected sleeve segments to force out the inner plug 448, the elasticretaining ring 472 acting to contract and thereby reduce the diameterprovided by the gripping segments so that the grip upon the pipeassembly is released.

With the plug seal means C clamped onto the forward end of the pipeassembly, the air under pressure in the main air line 57 and itsextensions passes out through the end 50 of the mandrel and into thegenerated pipe assembly to exert pressure against the plug seal means Cto advance the pipe assembly in an axial direction. this axial force isopposed by the axial force component of the continuous fiber elementsbeing pulled onto the pipe assembly at the stations where the devices J,J1, J2 and J3 are located; also, the coated strip or strips d furnish anopposing axial force component. The control means D located rearwardlyin the line from the forward extremity of the pipe assembly is a devicewhich synchronizes and controls the rate of advancement and the rate ofrotation of the pipe assembly. The device engages the rotating pipeassembly to revolve with it; the device as a whole does not travel withthe pipe assembly. The synchronization and control device D isconstructed to add or subtract linear work from the system bymaintaining the rate of linear advancement of the pipe assembly in aconstant relationship with respect to the pipe assembly's rate ofrotation. Such fixed relationship establishes the winding angle for thefiber elements constituting the hoop windings in the layers a, a1, a2and a3. When the correct relationship of rate of linear advancement torate of rotation of the pipe assembly is established, thesynchronization and control mechanism neither takes work out of thesystem to retard pipe advancement, nor does it put work into the systemto increase the rate of pipe advancement. However, when the axial thrustimposed by the air pressure to advance the pipe assembly is not in thecorrect relationship to the assembly's rate of rotation, thesynchronization and control means D, which is responsive to the rate ofadvancement of the pipe assembly, compensates the system by putting workin or taking work out to thereby maintain the desired constantrelationship of linear travel to rational movement of the pipe assembly.

As shown in detail in FIGS. 22-26, the control means D comprises anannular main support frame 482 in the form of a pair of spaced plates484, 484' secured in desired spaced relationship by a plurality ofcircumferentially located spacers 486. The main support frame has acentral opening of substantial size. A bolt 488 is extended through theframe plates and each of the spacers. The main support frame issupported for rotation within a load-bearing framework generallydesignated 490 which comprises a pair of transversely spaced standards492, 492' connected to one another by the vertically spaced top andbottom cross frame members 494, 494'. As shown in FIGS. 2E and 3E, thesupporting framework 490 is secured to a channel framework 496 which ispositioned on the floor and braced by angle irons 498, 498'. Anglebracing members 500, 500' are connected to extend between the standard492 and the bottom cross frame member 494 and between the standard 492'and the bottom cross frame member.

As shown in FIG. 25, bracing members 500, 500' each have mounted thereonthe load-bearing rollers 502, 502', respectively, to rotatably supportthe annular main support frame 482. To guide and maintain the supportframe in a fixed plane of rotation, three equidistantly spaced guiderollers 504 are mounted to extend between the frames' spaced plates 484and 484'. As shown in FIG. 26, each guide roller is of the ball bearingtype and is secured to a stub shaft or thrust rod 506 as by clamping awasher 508 to the inner race by a bolt 510 threaded into the end of thestub shaft. The opposite end of the stub shaft is fastened to thestationary framework. As shown in FIGS. 25 and 26, the top guide rolleris bolted to a tie bar 512 extending between spaced frame members 514,514' which also furnishes a support for a pillow block 516 for the driveshaft 266 (FIG. 3E). The drive shaft which actuates the aforementionedwinding heads I1, I2 and I3, also the conveyor tube forming device ordevices G, also actuates the control means D. As shown in FIG. 25, theother two guide rollers 504 are mounted at the ends of their respectivethrust rods 506 which are welded to brackets 518, 518' respectivelysecured to the standards 492, 492'. As will subsequently appear, theguide roller and thrust rod arrangements in the illustrated spacedrelationship, additionally function to sense axial thrust which may beimposed upon the main annular support frame 482 by the control device D.

As shown in FIGS. 2E and 3E, the annular main support frame 482 isrotated by the drive shaft 266 through a chain 520 cooperable with asprocket 522 fixed to the shaft. The chain 520 extends around a platesprocket 524 which has a central opening of substantial size and whichis of a slightly larger diameter than the annular frame support 482adjacent to which it is mounted. The sprocket 524 may be termed therotary control sprocket. The sprocket and the adjacent annular frame areconnected to one another for rotation together in any suitable manner,for this purpose, circumferentially spaced spacers 526 may be providedand held in position by the same bolts 488 as used for the spacers 486.

As shown in FIGS. 22 and 25, a hollow chassis 526 is positionedcentrally of the support frame 482 and the rotary control sprocket 524.The chassis may be cylindrical in form. As illustrated however, it ispreferred that the chassis be provided with intersecting sides tofacilitate the assembly therewith of the parts to be described. Asshown, the chassis is substantially square-shaped and has four sides sothat a pair of spaced, longitudinally extending channel member 530,530', 532, 532', 534, 534', and 536, 536' may be respectively secured toeach side of the chassis. The channel members extend forward andrearward of the chassis (FIG. 22) and the hollow character of thechassis allows the pipe assembly P to pass through the chassis and thecontrol device D.

Resilient annular members are mounted to grip the outer periphery of thepipe assembly at spaced areas about the rotating and linearly advancingpipe assembly P, the resilient members being mounted to revolve as aunitary assembly with the rotating pipe assembly and for independentrotation about their respective axes of rotation. As illustrated inFIGS. 22 and 25, the resilient annular members are in the form of tireseach of which is mounted upon the aforementioned longitudinallyextending channel members which are fixed to rotate with the rotarysupport frame 482 and the rotary control sprocket 526. With a four-sidedchassis, there are four pairs of longitudinally extending supportchannels and four pairs of tires 540, 540', 542, 542', 544, 544' and546, 546'. Preferably, the tires are of the inflatable or pneumatic typeto thereby afford, by the air pressure in them, means for adjusting thegripping pressure upon the pipe assembly. It will be understood that thenumber of pairs of tires is a matter of choice. Instead of four pairs,as illustrated, the device is operable with three pairs or more thanfour pairs depending upon the diameter of pipe being processed. Betweenthe channel members 530, 530', the axle for the rear tire 540 isjournaled in pivot brackets 548, 548' secured to the channels 530, 530',respectively. The front tire 540' is similarly mounted between this pairof channel members. The tires 542, 542', 544, 544' and 546, 546' aresimilarly mounted by brackets extending from the pairs of channelmembers 532, 532', 544, 544' and 546, 546', respectively. The channelmembers are each fastened as by welding to a pair of rings 550, 550'which are bolted to each side of the rotary control sprocket 524. Sucharrangement allows the ready replacement of a worn sprocket withoutdisturbing the connected assembly of chassis, longitudinally extendingchannel members and the spaced, resilient, rotatable pipe engagingelements or tires.

FIG. 23 illustrates how a tire, in this case tire 546, is mounted. Theother tires of the assembly are mounted in the same manner. An axle 552is fixed to extend between the brackets 548, 548' at one end of a pairof channel members, in this instance, the channel members 536, 536'. Ahub 554 is rotatable about the axle, the hub having bearings 556 and556' in each end. The hub has an ear 558 in the middle of its length towhich flanges 560, 560' are bolted at 652. The flanges extend from a rim564 for the annular resilient member or tire. The hub 554 is alsoprovided with a flange 566 at one end thereof to which a sprocket 568 isbolted at 570. Each of the eight tires is similarly mounted for rotationabout a fixed axis, and is provided with a sprocket 568.

Each of the longitudinally spaced tires 540, 540', 542, 542', 544, 544'and 546, 546' is driven off the same drive shaft 266 which rotates thedescribed rotatable assembly, which includes the tires as parts of suchrotatable assembly, to furnish axial control of the pipe assembly Pgripped by the tires. As shown in FIGS. 2E and 3E, a second drive isbrought off the drive shaft 266 through a second drive chain 572. Thechain 572 passes around a sprocket 574 fixed to the shaft 266, and asshown in FIGS. 22 and 25, such chain is cooperable with a sprocket 576which may be termed an axial control sprocket as distinguished from theaforementioned rotary control sprocket 524. Like the rotary controlsprocket, the axial drive sprocket is in the form of a plate and has acentral opening of substantial size to permit the chassis 528 to extendtherethrough. The sprocket 576 however, also has internal teeth (FIG.24) for cooperation with sprockets 578 on the input shaft of each offour differentials or gear reducers 580 which are circumferentiallyarranged for cooperation with the illustrated four pairs of tires. Toconfine the sprocket 576 to a fixed plane of rotation, the sprocket hasguide rings 581, 581' bolted to its sides, the rings extending to eachside of the circumferentially arranged, equidistantly spaced sprockets578 on the input shaft of each gear reducer. Each gear reducer is heldin a fixed position on the rotatable assembly by being fastened to aside of the four-sided chassis 528. On the output side of each gearreducer, two sprockets 582 and 584 are fixed to the same output shaft. Asprocket chain 586 extends over the sprocket 582 and the sprocket 568for each rear tire, thereby driving the rear tires 540, 542, 544 and 546in unison since the gear reducers are all of the same ratio. Also, achain 588 extends over the sprocket 584 of each gear reducer and thesprocket 568 for each front tire 540', 542', 544' and 546' to drive themat the same speed as the rear tires.

As will be apparent from the foregoing described relationship of theparts of the control means D, the resilient, annular members or tiresgrip the pipe assembly advanced centrally therethrough while rotatingbodily with the rotating pipe assembly P. The rotary motion imparted tothe tires about their respective axes of rotation through the medium ofthe axial drive sprocket 574, its associated gear reducers ordifferentials 580, and the chain and sprocket connections to theindividual tires, furnishes a control for the axial movement of thelongitudinally advancing pipe assembly. Axial movement of the pipeassembly may be interrupted when desired by disconnect means 589, onepart of which may be slidably mounted on the shaft 266 and the otherpart fixed to the sprocket 574 when a spline type of disconnect means isused. Under pressure, the air within the pipe assembly acts to resistthe pressure upon the pipe assembly which is imposed by the tires whichfirmly grip the outer periphery of the rotating and longitudinallyadvancing pipe assembly.

As previously indicated, the arrangement of guide rollers 504 and theirrespective stub shafts or thrust rods 506 have an additional function;they act to sense undue thrust which may be imposed upon the mainsupport frame 482 and the described associated parts which are assembledtherewith. As shown in FIG. 26, the thrust rod extends through alignedopenings 590, 590' on opposite sides of a housing 592 suitably fixed tothe stationary framework 490. The thrust rod is provided with a cavity594 extending into a side thereof intermediate its length within thehousing, the cavity terminating in stop 596. A thrust piston 598 has acentral shaft portion 600 the end of which is received within the cavity594 with its extremity 602 engageable with the stop 596. The shaft 600extends through an aperture 604 in the side wall of the housing 592. Anannular, externally threaded mounting sleeve 606 is secured as bywelding to the wall of the housing to surround the aperture 604. Thepiston 598 is positioned for reciprocation within a cylinder 608 whichis internally threaded at the rear portion thereof for connection to themounting sleeve 606. An O-ring 610 is positioned in a groove formedaround the head of the piston to prevent fluid leakage. A hydraulicfluid, such as oil, is contained within the cylinder 608 between thehead of the piston and flexible hoses 612 connected by suitable fittingsinto the internally threaded openings 614, 614' formed in the end wall616 of the cylinder.

As shown diagrammatically in FIG. 26A, three assemblies such as shown inFIG. 26 and designated D' are interconnected to one another by the hoses612, and a pressure sensing instrument or gauge 618 is tied into theline to sense any undue axial thrust which may be imposed upon or by thecontrol device by the pipe assembly. Undue axial thrust is sensed whenanyone of the three thrust rods 506 is unduly deflected about itscantilever connection to the stationary framework. Such deflections isconverted through the pistons 598 into hydraulic pressure. Variance froma predetermined gauge reading indicates that the axial thrust imposed bythe rollers 504 upon either of the rings 484 or 484' of the main supportframe 482 is out of balance. Appropriate correction is made by adjustingthe air pressure acting to impart axial thrust to the pipe assembly, orby adjusting the tension level on the rovings being applied from thewinding heads I, I2 and I3 which rotate the pipe assembly. The latteradjustment is made by changing the positions of the adjustable tensionguide ring 404 on each of the winding heads. As previously indicated,the drive shaft 266 actuates the control means D as well as serving torotate the winding heads I1, I2 and I3, also the conveyor tube formingdevice or devices G. The motor 258 which rotates the drive shaft eitherputs energy into the control device or acts as a brake when the systemwould tend to get out of balance, balanced conditions being apredetermined ratio of rates of linear advancement and of rotation ofthe pipe assembly. Since the same motor, or its shaft, actuates theoperations of aforementioned devices for incorporating material into thepipe assembly as well as serving to actuate the control device,temporary deviation from optimum balanced conditions does not seriouslyaffect the pipe assembly being generated; the operation of all of thedevices is synchronized from the same driving means to equally affecteach device.

The aforementioned inflatable means E is positioned within the pipeassembly P and forward of the control means D, as shown schematically inFIG. 1B. The inflatable means which, in effect, is an air piston, isshown in detail in FIGS. 27-34. The air piston is a device whichfurnishes a temporary, longitudinally advancing, internal air sealwithin the pipe assembly a set distance rearwardly from the end of thepipe while the pipe is being manufactured or generated. As previouslydescribed, the pipe assembly in the normal course of continuousmanufacture is air-sealed at its forward moving end by the plug sealmeans C, the air seal B over which the pipe assembly is drawn furnishingthe other end of the air sealed chamber. The air piston provided by themeans E permits cutting off a length of the pipe assembly from thecontinuously manufactured product without the loss of air pressurewithin the pipe assembly, and thereby the continuous manufacturingprocess need not be interrupted. Activating the inflatable air pistontemporarily creates a linearly travelling seal within the pipe assemblyto allow the removal of the plug seal means C from the end of the pipe,whereby a section or length of the otherwise endless pipe assembly beinggenerated may be cut on the unpressurized side of the travelling airseal provided by the means E. After a selected length of the pipe hasbeen cut from the continuously advancing pipe assembly, the plug sealmeans C is replaced in the end of the pipe whereby the air piston isthen relieved of the air pressure which actuates or inflates it. Whilesuch temporary air seal is operative, axial motion of the pipe ismaintained by the air pressure acting on this air piston form of deviceor plug. When the air seal is released, the air piston means B isautomatically returned to its unpressurized and rest position to awaitits next activation when a predetermined length of pipe assembly is tobe cut off from the endless pipe assembly being generated. FIGS. 27-31illustrate a pipe asembly P as related to the inflatable seal means E.For convenience of illustration, the pipe assembly is merely shown as atube, for without some showing thereof the related plug seal means C asshown in FIG. 28 would have no visible supporting means. It will beunderstood that the pipe assembly at this point in the line has theconstruction shown in FIG. 35.

As shown in FIGS. 27-34, the temporary air seal means E comprises aninflatable container 620 made of an elastic material such as rubber.When not activated or not inflated, the container has the form of a tubeclosed at each end, and has a diameter less than the internal diameterof the pipe assembly which rotates and advances over it. The clearancebetween the outer side of the inflatable container and the surroundingpipe assembly permits the air under pressure from the main air line toexert an axial thrust on the plug seal means C (FIG. 28).

The inflatable container 620, for a portion of its length, surrounds arigid support sleeve 622 made of aluminum or the like having a pluralityof openings 624 in its wall to place the interior of the support sleevein communication with the interior of the inflatable member. Theinflatable member is held to surround the support sleeve by forward endclamp means comprising an end clamp 626 which is welded to the forwardend of the support sleeve 622. The inflatable container is held bysecuring an end clamp 628 to the opposite side thereof, the clampingmembers 626 and 628 being held and secured to one another by a bolt 630extended through the clamp member 628 and threaded into the clamp member626 through an opening in the inflatable air container. The opposite orrear end of the inflatable container is clamped between a clamp member632 on the inner side and a centering guide 634 against which is presseda clamp member 636 by a nut 638. The nut is threaded onto an externallythreaded sleeve 640 which is secured as by welding to an air conveyingtube 642.

As best shown in FIG. 32, the air conveying tube 642 is in communicationwith the apertured or perforated support 622 surrounded by theinflatable container 620. As shown in FIG. 33, the air line 642 is incommunication with the tubing 98 connected to the second source of airback at the rotary coupling (FIG. 4). As previously described, thetubing 98 rotates with the mandrel A and extends beyond the mandrel'sforward end 50 or the end where the main air line 57 and its extensionsterminate. The diameter of the tubing 98 is smaller than the diameter ofthe tube 642. The end of the tube 98 is flared at 644 to allow relativelongitudinal movement between the tubes, and to prevent them from beingseparated.

As also shown in FIG. 33, the rearward end of the tube 642 is fastenedas by force-fitting into a guide hub 646 through which the tube 98extends. The guide hub is provided with an internal groove within whichis positioned an O-ring 648 to furnish an air seal between the hub andthe tube so that relative longitudinal motion between the tubes 98 and642 does not result in a loss of air pressure. A guide 650 for centeringthe pipe assembly over which the pipe assembly passes is secured as byscrews 652 to the guide hub. As shown in FIG. 30, the guide hub isprovided with longitudinally extending, circumferentially spaced holes653 to allow air from the main line to pass through the part and aroundthe deflated air container 620 for the application of thrust against theplug seal means C. The guide hub is also provided with a rearwardlyextending annular flange 654 of a diameter to closely surround the tube98. The hub having the air tube 642 connected thereto is slidable alongthe tube 98. As best shown in FIG. 34, a coiled tension spring 656 hasits forward end anchored to the hub member by providing the flangeportion 654 with annular grooves 658 within which several adjacent turnsof the spring are force-fitted. The spring acts to return the air pistonassembly, or the apertured support sleeve 622 and its surrounding aircontainer 620, to inactive position after the pressure in the lineprovided by the tubes 98 and 642 is released to deflate the aircontainer.

Accordingly, and as shown in FIGS. 27 and 28, the opposite or rear endof the spring 656 is anchored in the same way as the forward end, asabove described, to a centralizer tube 660 which is secured as bywelding to the outer periphery of the air conveying tube 98. Thecentralizer tube is secured to the air conveying tube 98 just forward ofthe control device D. The centralizer tube has mounted thereon aplurality of centralizer guiding ribs 662 with the ribs at their highestpoints having a diameter slightly less than the internal diameter of thepipe assembly which travels thereover and is guided thereby.

After a section of pipe has been cut off, the plug seal means C isclamped onto the forward end of the pipe assembly within the apparatus.The air container 620 which was inflated to frictionally grip theinterior of the pipe assembly to rotate and travel forward therewith isdeflated by releasing the pressure in the air line provided by thecommunicating tubes 98 and 642. The spring 656 acts to return theassembly including the deflated container, also the guide hub 650 andits associated parts, to a position adjacent the centralizer tube andits guide ribs. Upon subsequent reactivation of the air container 620,it becomes a travelling plug against which the air under pressure fromthe main line 57 and its extensions may exert an axial thrust to advancethe thus temporarily sealed pipe assembly. During such temporary seal ofthe pipe, the plug seal means C is unclamped, a section of the pipe iscut off, and the plug seal means is clamped into the forward cut end ofthe advancing pipe assembly without interruption of the continuousprocess.

An alternate embodiment of the means for providing the temporary fluidseal is illustrated in FIG. 43. In this embodiment the inflatablecontainer 620, described above, is attached to the forward end of ahollow rod 768 which is continuous over its entire length and extendsthrough the interior of the mandrel 57 and is slidably and rotatablyengaged with the rotary joint 774, which is at the rearward end of themandrel. The rotary joint 774 is attached to a supply line 814 throughwhich a fluid, for example, air, is fed into the mandrel. The hollow rod768 is attached at its rearward end to a rotary fitting 770. The rotaryfitting 770 is connected to a supply line 772 through which air oranother fluid under pressure can be fed from a source (not shown) toexpand the inflatable seal means 620. The rotary fitting 770 is attachedto one end of a cable 776 which passes from the rotary fitting over apulley 778 and is attached at its opposite end to a weight 780. Thepulley 778 is attached to the supporting member 812 through which thecable 776 and the rotary fitting 770 travel. The weight 780 ispositioned in a well (not shown) which preferably is filled with aliquid such as oil, which dampens the movement of the weight 780. Themeans for providing the fluid seal, as illustrated in FIG. 43, is in anengaged and almost completely extended position such as when it isutilized for cutting off a length of the generated pipe. After a lengthof the generated pipe has been cut off and the plug seal means Creinserted, the pressure on the fluid fed through the supply line 772 isreleased, which causes the inflatable seal means 620 to deflate anddisengage the walls of the generated pipe assembly as previouslydescribed. The weight 780 in combination with the cable 776 then causesthe assembly of the inflatable seal means 620, the hollow rod 768 andthe rotary fitting 770 to retract to the at rest position indicated inphantom in FIG. 43. The processing of pipe by the described apparatus isautomatic and continuous. As shown in FIGS. 2A and 3A, a control panel670 is mounted on the longitudinally extending central frame member 54for indicating the conditions of and for controlling several devices inthe system. An indicating potentiometer 672 is provided to control thetemperature for the heaters 312 which serve to partially cure the resinwhich provides the conveyor tube form of resin T. A voltmeter 674 alsoconnected to the heaters 312 serves as a temperature read out device. Arotary selector switch 676 permits temperature read out for any one ofthe plurality of heaters. Control means 678 is connected to the motor258 to control its speed, and a speed indicator 680 furnishes a read outof the actual rate of rotation of the motor's shaft 266.

Resin lined pipe produced by the specifically described automatic,continuous line is illustrated in FIGS. 35 and 35A. As previouslyindicated, the pipe construction, insofar as the number of layers andthe angles of winding of the fiber elements of the various layers, is amatter of choice. Changes may be made in the system for the structure ofpipe desired.

The apparatus hereinbefore described produces pipe having a continuousresin coating or layer on its interior supplied by the conveyor tube Twhich was made an integrated part of the finished pipe assembly. Bymodifying a portion of the described continuous system, an airimpervious conveyor tube T' may be provided which is removed from thepipe assembly after the conveyor tube has served its purpose offurnishing a base for the materials applied thereto in the conveyortube's advancement through the apparatus. Apparatus utilizing aremovable conveyor tube may produce pipe having a resin inner liner or apipe which is unlined.

The portion of the continuous system for making pipe with a removableconveyor tube is schematically shown in FIG. 36 and the structuredportion in FIGS. 37 and 39. When such portion of the apparatus at thebeginning of the system is placed in line with the remainder of thesystem as schematically shown in FIGS. 1A and 1B and structurally shownin FIGS. 2A-3D, a continuous system is provided for the automatic andcontinuous manufacture of a pipe assembly having a removable conveyortube T'.

Essentially, the conveyor tube T' is fabricated to furnish the desiredair impervious quality and the desired measure of rigidity to withstandthe forces of applying windings thereon under tension. Also, as will bedescribed, the conveyor tube includes as a part thereof means in theform of a stripping wire which enables the ready removal of the conveyortube which, in this embodiment of the invention, is included in the pipeassembly for processing purposes only.

Referring to FIGS. 36, 37 and 38, the conveyor tube T' is formed on therotatable mandrel A which, as hereinbefore described, serves to conveyair under pressure therethrough to impose an axial thrust for thelongitudinal movement of the pipe assembly through the system, also tosupport an auxiliary air line to the inflatable, temporary plug E. Atube of paper is first formed on the mandrel by applying a plurality ofstrips e to cover the mandrel. The strips, four in number in theillustrated form of the invention, are longitudinally applied to themandrel from four rolls 682 which are supported upon a sleeve holder 684fixed as by welding to the mandrel or the tube portion 57 thereof asbest shown in FIG. 40. The holder is provided with equidistantly spacedbrackets 686 to which the spindles 688 for the rolls of paper strip areconnected. The advancing pipe assembly of which the conveyor tube T' isa part serves to draw the paper strips off the rolls so that thelongitudinal edges of the strips are in slightly overlappingrelationship. The longitudinally applied strips are guided to assumesuch relationship by a guide member 690 provided with slots 692 extendedtherethrough as shown in FIG. 41. The guide member, which is providedwith a central aperture 694 to allow the tube portion 57 of the mandrelto extend therethrough, is suspended from longitudinally extending rods696 having their rearward ends fastened or welded to a pair of the rollholder brackets 686 (FIG. 39).

After the plurality of longitudinally extending paper strips e has beenlaid onto the mandrel with their edges overlapped, the strips areadhered to one another by an adhesive coating carried by a strip f whichis helically wound about them. The strip f prior to being wound aroundthe strips e passes over a coating roll 697 positioned in an adhesivebath 698 and is coated on one side. A heater 700 is disposed over theportion of the conveyor tube generated to dry or harden the adhesive. Asshown in FIGS. 37 and 38, the heater is suspended from longitudinallyspaced straps 702 secured to the upper central frame member 54.

As also shown in FIGS. 37 and 38, a pair of strips g and h helicallywound in the same direction about the material previously applied to themandrel, these latter two strips being drawn off of rolls 704 and 706mounted on stationary stands 708 and 710 adjacent the line. The strip gis of an air impervious material such as cellophane or vinyl resin film,and has an adhesive coating of a thermosetting resin, such as an epoxyresin composition, applied thereto by an applicator 712. The strip h ispreferably of a porous or absorbent material such as tissue paper. Whenboth strips are wound into the assembly and heat is applied as by asecond heater 713, the resin migrates through the strip h, the layersare bonded to one another and the tube is air impervious.

The portion of the conveyor tube T' thus far generated is then helicallyoverwound with two strips i and j, rolls of which are mounted on arotating head generally designated 714. The strip i is of paper and thestrip j is of a parting or mold release material such as a smooth tapeof polypropylene, Teflon or the like. The paper strip i is bonded to thegenerating conveyor tube through the medium of the resin adhesive whichhas passed to the outer side of the porous strip h. The rotating head714 also has mounted thereon a reel 716 from which a strong filament orwire k is drawn off and wrapped around the generated tube to lieadjacent the layer provided by the wound tape i. Incorporated in theconveyor tube, the stripping element or wire k lies at an angle ofapproximately 45° with respect to the longitudinal axis of the tube.When the pipe assembly of which the removable conveyor tube T' is a parthas been completed, pulling or applying tension to the stripping wire kcauses the destruction of the removable conveyor tube for its easyremoval from within the pipe assembly. The mold release layer providedby the tape j prevents adhesion of the conveyor tube to the resin innerliner of the pipe if a resin lined pipe is made, or to the resinimpregnant on the first layer a of continuous fiber elements wound intothe pipe assembly at the station J forward in the line. Due to thestaggered relationship of the strips i and j as they are being woundtogether, with the latter strip immediately overlapped upon the former,the mold release layer is firmly held on the outer side of the removableconveyor tube. The stripping wire k is beneath the layer formed by themold release strip j. When, after the pipe assembly is completed and apull is exerted upon the stripping wire, the conveyor tube beneath themold release layer is cut or destroyed and the mold release layerbecause of the character of the material readily comes away from theoverlying pipe structure.

As shown in FIGS. 38 and 39A, the rotating head 714 is suspended from abracket 718 secured at its upper end to the frame member 54. Therotating head comprises a circular plate 719 having a central opening toallow the generated conveyor tube to advance therethrough. The rotatinghead plate has a pair of diametrically opposed rearwardly extending rods720, 720', each of which is inwardly bent near their rear ends tofurnish spindles for the rolls of tape or strips i and j. A third rod722 is welded to the plate 719 and extends rearwardly and is formed toprovide a spindle for the wire wheel 716.

In the illustrated embodiment of the invention, as represented by FIGS.37, 38 and FIGS. 2A-3E, also as schematically shown in FIGS. 36, 1A and1B taken together, the mandrel is positively driven or rotated, whereasin the embodiment of the invention illustrated in FIGS. 2-3E andschematically in FIGS. 1, 1A and 1B, the mandrel though mounted forrotation is not powered or positively rotated. It is preferred topositively rotate the mandrel in synchronism with the rotation impartedto the pipe assembly in each of the illustrated embodiments of theinvention. Where the pipe is processed upon a conveyor tube of theremovable type, it is particularly desirable to positively rotate themandrel by bringing the drive from the motor 258 rearwardly to thebeginning of the line where, in addition to the drive mechanism coupledto the mandrel, a positive drive may be provided for the rotating head714.

As shown in FIGS. 38 and 39A, the plate 719 of the rotating head ismounted for rotation upon a stepped hub 724. The hub has the portionthereof of larger diameter abutted against the bracket 718 with itsportion of smaller diameter extended through the central opening of theplate 719. A plurality of circumferentially arranged screws 726 areextended through the bracket and screwed into the hub to affix the hubto the bracket. On the opposite side of the plate 719, a retaining plate728 is secured into the stepped portion of the hub by screws 730. Apulley 732 having a hub 734 is sandwiched between the plate 719 and thelarger diameter portion of the hub 724. The pulley is fixed for rotationwith the plate 719 by screws 736 extended through the plate and into thepulley hub 734.

The winding head 714 is rotated by a belt 738 around the pulley 732 andaround a second pulley 740 fixed to a countershaft 742 journaled inpillow blocks 744, 744' supported by the bottom frame 52, as shown inFIG. 38. The countershaft is rotated by the driven shaft 268 previouslyreferred to in connection with the first described embodiment of theinvention, and which, as previously described, is driven by the motor258. The shaft 268 and the countershaft 742 are provided with pulleys746, 746' and a cooperating belt 748. The shaft 268 extends furtherrearwardly in the line with the end of the shaft journaled in a pillowblock 750. The shaft 268 supplies power to rotate the mandrel A througha series of pulleys and belts. A pulley 752 is fixed to the shaft 268for cooperation with a pulley 754 fixed to a stub shaft 756. A belt 758is cooperable with the pulleys 752 and 754. The stub shaft which issuitably mounted for rotation in pillow blocks is provided with a pulley760 cooperable by means of a belt 762 with a pulley 764 fixed to themandrel or its tube portion 57.

The described drive mechanism, all off the same motor 258, impartsrotation to the winding head 714 so that the rotation of the mandrel issynchronized with the rotation of the rotating head 714 applying thetapes i and j to the generating, removable conveyor tube T'. It ispreferred that the drive means for the winding head 714 be arranged sothat the winding head shall rotate at a faster rate than the rate ofrotation of the mandrel to provide a wrap angle of less thanapproximately 45°. As shown in FIGS. 37 and 38, the completed removableconveyor tube T' may be overwound by a helically applied strip limpregnated or coated on both sides with a thermosetting resincomposition applied by resin applicator 766 to furnish a resin liner forthe completed pipe (after the tube T' is removed). If desired, the resinliner layer provided by the impregnated strip l may be omitted, wherebythe finished pipe comprises the plurality of layers of resin impregnatedcontinuous fiber elements applied by the devices J, J1, J2, J3, I1, I2and I3 forward of the portion of the line where the conveyor tube isformed on the mandrel.

Another embodiment of the invention where the conveyor tube is removableis illustrated in FIG. 43, the conveyor tube being designated 782. Atube winder 784 is rotatably mounted about the mandrel 57 on the support786 and is driven by a chain and sprocket drive 790. The tube winder 784comprises mounts 792 for holding rolls of tape 794, 796 and includesguides 798, 800. When the tube winder 784 is rotated about the mandrel57, tapes 794, 796 are helically wound on the mandrel to provide ahelically wound conveyor tube 782 on the mandrel. If desired, a singletape may be wound on the mandrel with the edge slightly overlapping toprovide the conveyor tube.

The strip material that is employed to furnish the removable conveyortube is nonadhesive on its inner surface to the mandrel 57 and is, orcan be, readily made adhesive on its outer surface. The interior isnonadhesive so that the conveyor tube will be free to advance over themandrel as the conveyor tube is advanced. The opposite or outer surfaceof the tube is coated with a separable adhesive, that is, an adhesiveeffective to adhere the tube to the resin composition of the pipe andwhich will allow separation of the tube from the resin composition inits polymerized or partially polymerized state upon treatment with aseparating agent. The separating agent is of a character or compositionwhich does not affect the polymerized or partially polymerized resincomposition.

In greater details, rolls of gummed kraft paper tape 794, 796 are loadedonto the tube winder 784. The tapes are then helically wound on themandrel 57 with the adhesive side out and the uncoated side toward themandrel. To eliminate as much of the friction as possible between theconveyor tube 782 and the mandrel 57, the mandrel 57 may be coated withTeflon. Since the adhesive surface is not adhesive in the dry state, theouter surface of the tube 782 is sprayed with a fine mist of water froma shower head 802. The water, in addition to moistening the adhesive onthe tape, somewhat dampens the paper and makes it more plastic so thatit will conform more smoothly to the contour of the mandrel 57. Afterthe conveyor tube 782 is moistened, it is dried by advancing it throughan oven 804. A resin liner 806 is applied to the conveyor tube from thenozzle 808. The resin liner 806 readily adheres to the dried adhesivesurface of the conveyor tube 782. The conveyor tube coated with theresin liner 806 is then advanced into a second infra-red oven 810 inwhich the resin liner is at least partially cured, and is thereby madeair impervious. The remainder of the glass and resin build-up is thenapplied to the coated conveyor tube. After the pipe assembly iscompleted, the conveyor tube 782 is removed from the finished pipe bysimply soaking the pipe in warm water or by the use of steam underpressure, which softens and dissolves the gummed adhesive and enablesthe paper tapes to be easily removed. If desired, the conveyor tube maybe left in the finished pipe to protect the inner resin liner until thepipe is ready for installation, whereupon the conveyor tube is removedin the field as above described just prior to installation of the pipe.

It will be apparent that the above technique is not limited to the useof the preferred water-soluble adhesive coated kraft paper and thatother materials having the above-noted properties may be used in lieuthereof. The carrier strip may be a solvent-permeable film, and theseparable adhesive may be a solvent activatable composition, whereuponthe conveyor tube is removed by soaking the tube lined finished pipe ina solvent bath in which the separable adhesive is soluble, but in whichdoes not affect the finished pipe assembly. Paper tape coated with awater-soluble adhesive is preferred because of economy and ease ofremoval with water or steam.

The apparatus shown in FIG. 43 may also be employed to manufacture pipein which the conveyor tube becomes an integral part of the finishedpipe. In this embodiment of the invention, tapes are initially preparedby resin impregnating a suitable base material such as fiberglass tape.The resin impregnated material is then preferably cured to a B-stage.The inner surface of the resin impregnated tape will not adhere to theTeflon coated mandrel 57 when wound on the mandrel. However, in order toinsure nonadhesion to the mandrel 57, a mold release agent such asgraphite can be applied to the inner surface of the tape or sprinkled onthe mandrel 57 as the tapes are wound onto the mandrel 57. The outersurface of the tape can be made adhesive by several differenttechniques. The outer surface of the resin impregnated tape can becoated with a suitable semicured thermosetting adhesive resin. Inaddition, with certain resins, a fine mist of selected solvents can beapplied to the conveyor tube from the shower head 802, which makes theouter surface adhesive in a manner similar to that noted above thegummed kraft paper tube. Resinous materials may also be employed whichwhen initially heated in the oven 804 will become somewhat softer andadhere to the surface of adjacent tapes before the resin advances incure from the B-stage to the C-stage. An additional method of formingthe integral air impervious conveyor tube is to coat the helically woundresin impregnated tape with a coating of resin 806 from the nozzle 808,and at least partially cure the resin coating so as to completely sealthe outer wall of the conveyor tube. Once the conveyor tube is formed asnoted above, it is then further built up as indicated above to providethe finished pipe.

An additional embodiment of the present invention is illustrated inFIGS. 46 and 47. Referring to FIGS. 46 and 47, the number 816 generallydesignates an apparatus for forming continuous glass-reinforced plasticpipe in accordance with the present invention. The apparatus 816comprises a vertical stationary rigid supporting member 818, which maycomprise a portion of a suitable supporting frame, not shown, saidsupporting member 818 being formed with a horizontal projection 820containing a horizontal bore 822. Journaled axially in the bore 822, asby means of suitable ball bearing assemblies 824 and 826, is rigidtubular shaft 828 on which is coaxially mounted the pipe forming mandrel830. As shown in FIG. 47, the mandrel 830 is located adjacent the end ofthe projection 820 and is formed with longitudinally extendingsupporting flanges 832 extending from the end of the mandrel 830parallel to and over the projection 820. The longitudinally extendingsupporting flanges 832 are angularly spaced uniformly around the axis ofthe mandrel 830, and each longitudinally supporting flange 832 is formedwith a radially extending supporting flange 834.

Journaled on the end of each outwardly projecting radially extendingflange 834 adjacent to the supporting member 818 is a feed roll 836 ofadhesive coated cellophane tape such as Scotch brand tape, and journaledon the radially extending flange 834 forwardly adjacent the feed roll836 is a feed roll 838 of cellophane strip material. The respective feedrolls 836 and 838 are so arranged relative to each other, and the stripmaterial carried thereon is of sufficient width, so that the cellophanestrips from the roll 838 can extend longitudinally onto the mandrel 830with their side edges substantially in engagement with each other andwith their side margins overlapping and adhesively secured on the stripsof adhesive coated cellophane tape from the roll 836, which are likewiselaid longitudinally on the mandrel 830. Thus, the strips of adhesivecoated cellophane tape are designated in FIG. 46 at 840 and theside-by-side strips of cellophane from the rolls 838 are designated 842.

Suitably journaled adjacent to the mandrel 830 on an axis which isinclined at an acute angle to the axis of the mandrel is a supply roll844 of glass tape 846 impregnated with a thermosetting resin. As shownin FIG. 46, the roll 844 is positioned so that the glass tape 846 can behelically wound over the air tight envelope formed by the cellophanestrips 842 and the adhesive coated cellophane tape strips 840 connectingtheir margins, the glass tape 846 having its major strength in asubstantially transverse direction so that the finished pipe is providedwith the required strength in its axial direction.

The mandrel 830 is provided with a series of longitudinally spacedannular peripheral air pressure equalizing grooves 848, 850 and 852, fora purpose presently to be explained, the groove 848 being locatednearest the left end of the mandrel 830, as viewed in FIG. 47. The glasstape 846 is applied to the mandrel at a location substantially betweenthe groove 848 and the adjacent groove 850.

Vertically journaled adjacent the supply roll 844 and spaced forwardlytherefrom in the manner indicated in FIG. 46 are a plurality ofglass-roving supply packages 854, the glass roving supply packages 854being spaced so that the glass strands therefrom can be convergedthrough a stationary guide ring 856 mounted adjacent the forward end ofthe mandrel 830 and so that the strands, shown at 858, can be appliedtherefrom, in a desired configuration, for example, in parallelrelationship in accordance with the horizontally elongated shape of theguide ring 856, onto the previously wound layer of glass tape 846. Theparallel strands 858 emerging from the guide ring 856 are preferablyapplied in the same direction as the glass tape 846, and are therebyhelically wound onto the subjacent helically wound layer of glass tape846 in the manner illustrated in FIG. 46 responsive to the rotation ofthe formed pipe, in a manner presently to be described.

Mounted forwardly adjacent the guide ring 856 and in any desiredlocation around the axis of the formed pipe are a plurality oflongitudinally arranged heaters 860 which may extend through any desiredlength so as to apply heat to the pipe being fabricated over acorresponding length of the pipe, which may, in some instances, consistof one hundred feet or more of pipe length. The initial heat suppliedfrom the heating units 860 softens the thermosetting resin of the glasstape 846 and allows the strands 858 to become embedded in the glass tape846 to form a composite laminar structure. The thermosetting resin isthereafter cured as the pipe continues to advance past the heaters 860.

Glass tape 846 from supply rolls 844 and glass strands 858 from rovingpackages 854 may be applied as many times as is necessary to build upthe finished pipe to the required wall thickness. The heat which isapplied to the superimposed material by the heaters 860 polymerizes thethermosetting resin. Depending on the rate of production, the heat maybe applied over any desired length of the pipe being fabricated, forexample, over a length of a hundred feet or more.

Secured to the forward end of the tubular shaft 828 is a piston assembly861 comprising a main cylindrical disc member 862 which is secured tothe tubular shaft 828 by an axially extending fastening bolt 864 asshown in FIG. 47, and clamps a resilient deformable sealing cup 866against an inner rigid washer 868. The sealing cup 866 is preferablymade of polytetrafluoroethylene (Teflon), and provides a seal incombination with the inside surface of the formed pipe.

Connected to the forward end of the shafts 828, as by a rotary sealingcoupling 870, is a compressed air supply conduit 872 which furnishes airunder pressure through the sealed rotating connection 870 to the tubularshaft 828. The tubular shaft 828 is formed adjacent the piston washer868 with a discharge aperture 874 through which compressed air isdischarged into the space 880 between the piston assembly 861 and themandrel 830 and substantially fills said space 880 also penetrating intothe circumferential space around the mandrel 830 to provide an aircushion between the mandrel 830 and the inside surface of the pipeformed thereon. The air pressure is equalized circumferentially aroundthe mandrel 830 by the provision of the equalizing grooves 848, 850, 852so that channelling of the compressed air along the peripheral surfaceof the mandrel is prevented, maintaining substantially uniform airpressure around the periphery of the mandrel and maintaining asubstantially uniform air cushion between the peripheral surface of themandrel and the inside surface of the formed pipe. The equalizing groove848 communicates by means of radial passages 876 with an annular endcavity 878 provided in the mandrel 830, said cavity 878 being exposed toatmosphere, whereby the air is allowed to bleed through the passages 876and escape freely so that air is not forced to flow out between theunsupported cellophane and the forming mandrel 830. The air pressure issuch as to expand the pipe only to the amount required to support thepipe properly while it is cured and to provide the air cushion betweenthe inside surface of the formed pipe and the periphery of the formingmandrel 830, so as to allow the pulling means D described above to movethe pipe axially in a smooth and efficient manner. Thus, as the pressurebuilds up in the space 880, air leaks out between the forming mandrel830 and the inside surface of the formed pipe, allowing the air pressureto automatically adjust to the desired value. Thus, the pipe floatsfreely on the forming mandrel 830 because of the presence of theaforementioned air cushion, sufficient air being fed into the pipe tocause it to then expand circumferentially to a sufficient degree tosustain the winding load imposed thereon from the glass roving strands854 and the glass tapes 846.

The pulling frame designated by the letter D in FIG. 46 is identical instructure to the apparatus described above and shown in FIG. 22. Thepulling frame D is arranged coaxially with the mandrel 830 and is spaceda substantial distance forwardly of the heaters 860 and a short distancerearwardly of the piston assembly 861, as shown in FIG. 46. The tires540 attached to the pulling frame D extend inwardly and frictionallyengage the periphery of a cured pipe 882 extending from the mandrel 830.The rotation of the pulling frame D, as described above, causes thetires 540 to engage to cured pipe 882 and to pull the pipe 882forwardly, while the pipe 882 is simultaneously rotated by the pullingframe D.

In operation, the cellophane strips 842 are fed over the adhesive coatedcellophane tape strips 840 so that their side edges are closely adjacentto each other to form a substantially air-tight casing on the mandrel830. The glass tape 846, impregnated with a thermosetting resin, asabove described, is fed from the roll 844 at an angle such as thatillustrated in FIG. 46, being wound over the cellophane strips 842 in ahelical fashion between the annular grooves 848 and 850 of the mandrel830, as shown in FIG. 46. The supply roll 844 is positioned so as toprovide the desired pitch angle for the wound glass tape 846. Similarly,the glass fiber roving strands 858 are furnished from the rovingpackages 854 and fed through the guide ring 856, in the manner abovedescribed, at a location forwardly spaced from the glass tape 846, asshown in FIG. 46, being helically wound on the wound tape 846 and beingapplied at a location spaced rearwardly from the groove 850 of themandrel and being located adjacent to or overlying the groove 852. Boththe glass tape 846 and the glass fiber roving strands 858 are fed underadequate tension so as to provide a close wrap. As above mentioned, theglass tape 846 and the roving strands 858 may be applied as many timesas is necessary to build up the finished pipe to the required wallthickness. It will be understood that the winding of the tape 846 andthe glass fiber roving strands 858 takes place because the cured pipe882 is being rotated and simultaneously pulled forwardly by the actionof the pulling frame D above described.

Heat is applied to the material by the heaters 860 to polymerize thethermosetting resin, and the heat is applied over a length of pipeforwardly of the mandrel 830, depending upon the rate of production. Asabove mentioned, the heat may have to be applied, in some cases, to overa hundred feet or more of pipe length.

The portion of the pipe between the mandrel 830 and the pulling frame Dis held in proper shape by the air pressure supplied to the space 880 inthe manner above described, the compressed air being fed through thetubular shaft 828 and discharging in the space 880 through the aperture874. The pressure is sufficiently high to cause the pipe to expandcircumferentially to sustain the winding load imposed on the pipe by theroving strands 858 and the glass tape 846, as above described, theexpansion allowing the pipe to float free of the forming mandrel 830,enabling the puller D to move the pipe axially over the forming mandrel830 and the piston assembly 861 at the forward end of the shaft 828. Asthe pipe is expanded, the air leaks out between the forming mandrel 830and the cellophane inner casing of the pipe, the air pressure being thusautomatically adjusted so that the pipe is expanded only to the degreerequired to adequately reduce the friction between the inner casing ofthe pipe and the forming mandrel, and so that the puller D can easilymove the pipe axially.

The pipe and puller assembly D are supported by sprocket chains 886 and890, whereas the driving power is furnished by the electric motor 892.

The tubular shaft 828 is preferably slidably adjustable relative to themandrel 830 to permit starting-up operation of the machine.

It will be noted that the apparatus illustrated in FIGS. 46 and 47includes several important features from the standpoint of design andoperation. First, all glass and resin delivery systems are fixed. Thisis a very important requirement for continuous production machines,particularly for large diameter pipe. The only revolving materials arethe cellophane and adhesive coated cellophane tape. Secondly, airpressure is used to balance the winding tensions and to support the pipeover long lengths so that the pipe may be passed unsupported through along curing oven. This will allow the pipe to be produced at a very highproduction rate. The air pressure also reduces the friction between thecellophane release layer and the forming mandrel 830. By using airpressure there is no limit to the wall thickness to which the pipe canbe fabricated, since the more material that is applied, the more airpressure can be furnished to balance same. Thirdly, the puller assemblyD operates on a fully cured section of the pipe which is internallysupported by air pressure. Thus, the puller is enabled to simultaneouslyrotate the pipe and move it axially over the forming mandrel 830 andthrough the curing oven.

Fourthly, a reinforced plastic pipe or tube may be fabricated with athick resin inner liner that would be in compression during operatingconditions. A resin coat would be applied to the cellophane casing andcured by suitable heaters before the overwind of glass tape and rovingis applied. The mandrel at this point would be reduced in diameter sothat the overwind of glass tape and roving would put the thick resinliner in compression. To present a resin lining, the inner cellophanerelease layer, of course, would have to be stripped from the pipe in aconventional manner. A plastic pipe with a resin liner in compressioncan operate at much higher stress levels and for longer periods of timethan present reinforced pipe.

It will be apparent that in devising the automatic, continuous sytemsfor the manufacture of fiber reinforced plastic pipe illustrated inFIGS. 1-47 above, a number of devices have been included which possessutility for other purposes than as herein before specifically describedin connection with the manufacture of fiber reinforced plastic pipe. Thedevice G has general utility for coating strip or sheet material. Thebelt system F may be used for forming a resin tube apart from having thetube formed on such system overwound with additional material ormaterials. The winding head I and the manner of coating the continuousfiber elements drawn off the head may be used for the application ofbands or layers of fiber elements to any hollow article of substantiallength, for example, the manufacture of a structural body which may havea configuration other than cylindrical. Also, the control device D maybe used in processing any cylindrical member or pipe such as metal pipe.The plug seal means C, while particularly adapted for use in conjunctionwith a pipe assembly generated as specifically described, is also usefulwhere it may be desired to process metal pipe by coating the same orotherwise treating the continuously advanced pipe or tubing. The airpiston E may be used in conjunction with a rigid metal pipe or tuberather than in a system which fabricates the pipe as described.

It is believed that the advantages and improved results afforded by theinvention will be apparent from the foregoing specifically describedpreferred embodiments of the invention. It will be apparent that variousmodifications and changes may be made without departing from the spiritand scope of the invention as sought to be defined in the claims whichfollow.

I claim:
 1. A method for continuously making substantially rigid, fiberreinforced plastic pipe comprising providing an air impervious conveyortube on an axially fixed, hollow mandrel, the mandrel being providedwith means to furnish an air seal with the interior of the conveyor tubeas the conveyor tube is continuously advanced over the mandrel, windinga plurality of bands of thermosetting resin composition impregnatedcontinuous fiber elements onto the conveyor tube to provide a pipeassembly, rotating the pipe assembly with respect to the mandrel, curingthe thermosetting resin composition, providing an air seal at theforward end of the pipe assembly being generated, linearly advancing thepipe assembly by directing air under pressure through the mandrel andout from the forward end thereof into the interior of the pipe assembly,.[.and.]. controlling the rate of linear advancement of the pipeassembly.[...]. .Iadd.and providing a temporary seal to prevent the lossof pressure within the advancing pipe assembly when a section thereof iscut and to allow providing an air seal at the forward end of the pipeassembling being generated. .Iaddend.
 2. A method according to claim 1,wherein a resin tube is provided beneath the bands of thermosettingresin composition impregnated continuous fiber elements.
 3. A methodaccording to claim 1, wherein the air impervious conveyor tube is of aresin composition.
 4. A method according to claim 1, wherein providingan air impervious conveyor tube on the mandrel comprises forming on themandrel a tube of a thermosetting resin composition, and at leastpartially curing the resin composition prior to winding a band ofthermosetting resin composition impregnated continuous fiber elementsthereon, said tube being integrated into the pipe assembly to furnish aresin liner.
 5. A method according to claim 1, wherein providing an airimpervious conveyor tube on the mandrel comprises impregnating acontinuous carrier strip with a thermosetting resin composition toprovide the resin composition on both sides of the carrier strip,providing a portion of the length of the mandrel with a partingmaterial, winding the resin impregnated carrier strip on said portion ofthe mandrel to form a tube, and at least partially curing the resincomposition prior to winding a band of thermosetting resin compositionimpregnated continuous fiber elements thereon, said tube beingintegrated into the pipe assembly to furnish a resin liner.
 6. A methodaccording to claim 1 wherein providing an air impervious conveyor tubeon the mandrel comprises impregnating a continuous carrier strip with athermosetting resin composition, at least partially curing said resincomposition prior to winding it on the mandrel, providing a portion ofthe length of the mandrel with a parting material, winding the at leastpartially cured resin impregnated carrier strip on said mandrel to forma tube; sealing the wall of said tube to make it air impervious prior towinding a band of thermosetting resin composition continuous fiberelements thereon, said tube being integrated into the pipe.
 7. Themethod according to claim 6 wherein said thermosetting resin compositionimpregnated carrier strip is cured to a B-stage prior to being wound onsaid mandrel, said sealing comprising heating said resin compositionimpregnated strip material after it is wound on said mandrel to atemperature sufficient to cause said B-stage resin to soften and fusewith the resin composition on adjacent strips of said strip material,thereby forming said air impervious tube.
 8. The method according toclaim 6 wherein said sealing is provided by applying a continuouscoating of a resin composition over the tube, and at least partiallycuring said coating prior to overwinding a band of thermosetting resincomposition impregnated continuous fiber elements thereon.
 9. A methodaccording to claim 1, wherein the air impervious conveyor tube is formedto enable the removal thereof from within the completed pipe assembly.10. A method according to claim 1, wherein providing an air imperviousconveyor tube on the mandrel comprises forming the tube on the mandrel,the tube having a layer of parting material at the exterior thereofwhereby the conveyor tube may be removed after the pipe assembly iscompleted.
 11. A method according to claim 1, wherein providing an airimpervious conveyor tube on the mandrel comprises forming the tube onthe mandrel, the tube having a layer of parting material at the exteriorthereof, the tube including a stripping wire adjacent the layer ofparting material, and applying tension to the stripping wire to removethe conveyor tube after the pipe assembly has been completed.
 12. Amethod according to claim 1 wherein the air impervious conveyor tube isformed with a resinous outer liner which becomes integral with the pipeand a removable inner liner.
 13. The method according to claim 12wherein the outer surface of said inner liner is coated with a layer ofa solvent activated parting agent, whereby said inner liner is releasedby contacting the parting agent with the solvent for the parting agent.14. A method according to claim 1 wherein producing an air impervioustube on the mandrel comprises providing a tape having an inner surfacewhich is nonadhesive to said mandrel and a coating of a solventactivated parting agent on the outer surface thereof, helically windinga tape about said mandrel to provide a tube with the inner surface ofsaid tape adjacent said mandrel, coating the outer surface of said tubewith a thermosetting resin composition and at least partially curingsaid resin composition prior to winding a band of thermosetting resincomposition impregnated continuous fiber elements thereon.
 15. A methodaccording to claim 14 wherein the parting agent is activated by water.16. A method according to claim 14 wherein the tape is of paper coatedon one side with a water-soluble adhesive.
 17. A method according toclaim 1, wherein winding a plurality of bands of thermosetting resincomposition impregnated continuous fiber elements onto the conveyor tubecomprises winding one set of bands having the fiber elements thereof ata high angle with respect to the longitudinal axis of the pipe assemblyalternated with a second set of bands wound with the fiber elements at alower angle and of opposite hand, rotating the pipe assembly by thewinding of one of said sets of bands.
 18. A method according to claim 1,wherein winding a plurality of bands of thermosetting resin compositionimpregnated continuous fiber elements onto the conveyor tube compriseswinding one set of bands having the fiber elements thereof at a highangle with respect to the longitudinal axis of the pipe assemblyalternated with a second set of bands wound with the fiber elements at alower angle and of opposite hand, the fiber elements of adjacent pairsof hands being impregnated by a resin composition in the same bath. 19.A method according to claim 1 which includes providing an inflatable airseal .Iadd.as said temporary seal .Iaddend.within the pipe assemblyrearward of the forward end of the pipe assembly, the air seal wheninflated being movable with the advancing pipe assembly, inflating theair seal and cutting off a selected length of the advancing pipeassembly, thereby preventing the loss of pressure within the pipeassembly being generated, permitting uninterrupted advance of the pipeassembly and allowing positioning of the air seal on the forward end ofthe advancing pipe assembly.
 20. A method according to claim 1, whereinthe rate of linear advancement of the pipe assembly is synchronized withthe rate of rotation of the pipe assembly, the rates of linearadvancement and of rotation being responsive to power from a singlesource.
 21. A method for making plastic pipe comprising forming aconveyor tube on a mandrel, the conveyor tube including at the exteriorthereof a layer of parting material and a stripping wire adjacent saidlayer, winding a plurality of bands of resin impregnated fiber elementsonto the conveyor tube to provide a pipe assembly, advancing the pipeassembly, and stripping the conveyor tube from within the pipe assemblyby pulling on the stripping wire.
 22. A method according to claim 21,wherein forming the conveyor tube on a mandrel comprises winding aplurality of strips on the mandrel and adhesively uniting the layersprovided by the strips, winding a pair of strips including a strip ofparting material in staggered relationship onto the assembly of layersand simultaneously winding a stripping wire between the staggered stripsto secure the stripping wire between the strips, the strip of partingmaterial being positioned on the exterior of the conveyor tube.
 23. Amethod according to claim 21, wherein the fiber elements in each bandare continuous and in parallel relationship wherein the resin impregnantfor the fiber elements is a thermosetting resin composition; and whereinthe resin impregnant is cured prior to pulling on the stripping wire toremove the conveyor tube from within the pipe assembly.
 24. In a methodfor making fiber reinforced plastic pipe wherein a resin composition andfiber reinforcement are applied about a mandrel, the improvement whichcomprises providing a tube on the mandrel which is nonadhesive theretoon the side adjacent the mandrel, said tube having a separable adhesivecoating on the opposite side effective to adhere the tub to the resincomposition and to allow separation of the tube from the resincomposition upon treatment with a separating agent, the resincomposition in its polymerized state being unaffected by the separatingagent, applying a resin composition and fiber reinforcement around thetube coated as aforesaid and polymerizing the resin composition to formthe pipe, treating the separable adhesive coating with a separatingagent, and removing the tube from within the pipe.
 25. In a methodaccording to claim 24 wherein the tube is of paper and the separableadhesive is a water soluble composition.
 26. In a method according toclaim 25 wherein prior to applying the resin composition and fiberreinforcement, water is applied to the water soluble adhesive coating tomoisten the coating and dampen the paper, drying said coating, applyinga heated resin composition coating to the water soluble adhesivecoating, and at least partially polymerizing the resin composition. 27.In a method according to claim 25 including applying water to the tubewithin the pipe to cause separation of the paper tube from the pipe, andremoving the paper tube from within the pipe.
 28. In a method accordingto claim 26 including applying water to the tube within the pipe tocause separation of the paper tube from the pipe, and removing the papertube from within the pipe.
 29. In a method according to claim 25,wherein the tube comprises a pair of paper tapes coated with the watersoluble composition helically wound upon the mandrel with their edges inoverlapping relation.
 30. In a method according to claim 29 includingapplying water to the tube within the pipe to cause separation of thepaper tube from the pipe, and removing the paper tube from within thepipe.
 31. A method of forming plastic pipe comprising applying strips offlexible release material longitudinally onto a mandrel in abuttingrelationship, applying adhesive strips beneath the side margins of thefirst-named abutting strips, whereby to form a release liner, windingstrip material impregnated with a thermosetting resin onto the releaseliner, winding glass roving strands onto said strip material, heating topolymerize said resin, and supporting the release liner internally byinflating same with fluid under pressure during the heating of thesuperimposed materials.
 32. A method of forming plastic pipe accordingto claim 31, wherein said fluid is allowed to escape at a restrictedrate between the mandrel and the release liner, whereby to provide asupporting layer of fluid between the mandrel and the release liner. 33.A method of forming plastic pipe comprising applying strips of flexiblematerial longitudinally onto a mandrel in abutting relationship,applying adhesive strips beneath the side margins of the first-namedabutting strips, whereby to form a release liner, coating the releaseliner with a thermosetting resin, curing the thermosetting resin withsuitable heat to provide a cured resin layer, winding a second stripmaterial impregnated with a polymerizable resin over the cured resinlayer at a point where said mandrel is reduced in diameter winding glassroving strands onto said second resin impregnated strip material, thusputting the cured resin layer in compression, heating the superimposedmaterials to polymerize the resin of said second resin impregnatedstrip, supporting the release liner internally by inflating same withfluid under pressure during the heating of said superimosed materials,and allowing fluid to escape at a restricted rate between the mandreland the release liner, whereby to provide a supporting layer of fluidbetween the mandrel and the release liner.